1. Exponents-word problem

    A culture starts at 8600 bacteria. After one hour the count is 10,000. Find a function that models the number of bacteria n(t) after t hours. The answer is n(t) = 8600e^.1506t Where does this 0.1506 come from? Thanks. n(t) = 8600 e^(kt), where k is an
  2. math

    A culture starts with 8300 bacteria. After one hour the count is 10,000. (a) Find a function that models the number of bacteria n(t) after t hours. (Round your r value to three decimal places.)
  3. Urgent math

    population growth model. Can anybody please help me out in trying to solve this problem? It's my homework and I don't seem to understand what I am getting. The count in a culture of bacteria was 400 after 2 hours and 25,600 after 6 hours. (a) What is the
  4. Urgent math

    The initial size of a culture of bacteria is 1000. After one hour the bacteria count is 4000. (a) Find a function n(t) = n0ert that models the population after t hours. n(t) = b)Find the population after 1.5 hours. (Round your answer to the nearest whole
  5. PreCalc

    The initial size of a culture of bacteria is 1500. After 1 hour the bacteria count is 12000. (a) Find a function n(t) = n0e^rt that models the population after t hours. (Round your r value to five decimal places.) n(t) = (b) Find the population after 1.5
  6. Precalculus

    NEED HELP ASAP PLEASE!! A bacteria culture starts with 2000 bacteria and the population doubles every 3 hours. a) A function that models the number of bacteria after t hours is p(t)=____________? b) The number of bacteria present after 5 hours will be
  7. Calc

    The number of bacteria in a culture is increasing according to the law of exponential growth. There are 125 bacteria in the culture after 2 hours and 350 bacteria after 4 hours. a) Find the initial population. b) Write an exponential growth model for the
  8. MATH :)

    3. In Biology, it is found that the bacteria in a certain culture double every half-hour. If the initial number of bacteria in culture is 1000, A. Find the defining equation for the number N of bacteria in culture after T hours, assuming that no bacteria
  9. precalculus

    A bacteria culture initially contains 1500 bacteria and doubles every half hour. a) Find an expression for the number of bacteria after t hours. Q(t)= b) The number of bacteria after 20 minutes is (the answer must be an integer) c) The number of bacteria
  10. Math

    A culture contains 12,000 bacteria. After an hour the count is 25,000. Find the number of bacteria after 3 hours.
  11. Algebra 2

    If there are initially 1500 bacteria in a culture, and the number of bacteria double each hour, the number of bacteria after t hours can be found using the formula N=1500(2^t). How many bacteria will present after 7 hours? I think the answer is N=192,000.
  12. Pre-Calc/Trig...

    is this the correct formula for me to solve this? A bacteria culture has 2,000 bacteria. The number of bacteria increases by 5% each hour. How many bacteria are there after 12 hours? 2,000*0.05^(12-1)
  13. pre calculus

    if there are initial 2500 bacteria in a culture, and the number of bacteria double each hour, the number of bacteria after t hours cab n be found using the formula=N=2500(2^t).how long will it take the culture to grow to 75,000 bacteria.
  14. math

    The number of bacteria in a culture is modeled by: n(t) = 1330e^(0.42t) (a) The initial number of bacteria is: (b) The relative rate of growth of this bacterium population is: (c) The number of bacteria after 3 hours is: (d) After how many hours will the
  15. Calculus

    Suppose that a population of bacteria triples every hour and starts with 700 bacteria. (a) Find an expression for the number n of bacteria after t hours. n(t) = ? (b) Estimate the rate of growth of the bacteria population after 1.5 hours. (Round your
  16. Math

    he number of bacteria in a culture is modeled by n(t)=1710e071t (a) The initial number of bacteria is (b) The relative rate of growth of this bacterium population is (c) The number of bacteria after 3 hours is (d) After how many hours will the number of
  17. math

    The number of bacteria in a culture is modeled by n(t)=1710e071t (a) The initial number of bacteria is (b) The relative rate of growth of this bacterium population is (c) The number of bacteria after 3 hours is (d) After how many hours will the number of
  18. Maths

    the count of bacteria in a culture was 525000. if it is increasing at the rate of 3 1/2% per hour find the count of bacteria at the end of 2 hours.
  19. calculus

    2. The rate of change in the number of bacteria in a culture is proportional to the number present. In a certain laboratory experiment, a culture has 10,000 bacterial initially, 20,000 bacteria at time t1 minutes, and 100,000 bacteria at (t1 + 10) minutes.
  20. math

    A bacteria culture starts with 1,000 bacteria and doubles in size every 2 hours. Find an exponential model for the size of the culture as a function of time t in hours.
  21. math

    A bacteria culture starts with 1,000 bacteria and doubles in size every 2 hours. Find an exponential model for the size of the culture as a function of time t in hours. f(t) = 1
  22. math

    A bacteria culture starts with 260 bacteria and grows at a rate proportional to its size. After 4 hours there will be 1040 bacteria. (a) Express the population after t hours as a function of t. this is what i put as my answer but i guess its not right do i
  23. calculus

    A bacteria culture starts with 900 bacteria and the population doubles every 4 hours. Find an expression for the number of bacteria after t hours.
  24. Algebra

    A certain culture initially contains 10,000 bacteria and increase by 20% after every hour. A) What will be the formula for numbers N(t) of bacteria after "t" hours? B) How many bacteria are in culture at the end of 10 hours?
  25. Calculus (math)

    A bacteria culture grows with constant relative growth rate. The bacteria count was 784 after 2 hours and 117649 after 6 hours. What is the relative growth rate? What was the initial size of the culture? Find an expression for the number of bacteria after
  26. Math

    I have this hard question in math. can someone help me find out the riddle? I start with 1 bacteria. Every hour it doubles. How many hours until there are 1,000,000 bacteria? Can you make a function that describes this situation? What if I double it? I
  27. College Algebra

    The number of bacteria in a certain culture increased from 500 to 1000 between 7:00 A.M. and 9:00 A.M. Assuming growth is exponential, the number f(t) of bacteria t hours after 7:00 A.M. is given by f(t) = 500(2)^t/2. (a) Estimate the number of bacteria in
  28. Math

    A certain type of bacteria is growing at an exponential rate that can be modeled by the equation y=ae^kt, where t represents the number of hours. There are 300 bacteria initially, and 1500 bacteria 5 hours later. How many bacteria will be present at time
  29. Maths

    Bacteria in a culture grow 15 per thousand in an hour. If the count of bacteria in a sample is 1000000,after 2 hours it will be (a)1030225 (b)1080225 (c)1030125 (d) 1030200 The correct answer is option (a) help me to find the answer.
  30. Math

    In a lab experiment, the count of a bacteria doubles every hour. a)at 1pm, there was 23000 bacteria. How many bacteria will be present at midnight? I can't seem to get the correct answer. The answer is 47 104 000 bacteria. Thanks very much in advance!
  31. math 12

    The bacterium Escherichia coli, or E-coli, has a doubling period of 0.32 h. If a culture starts with 100 bacteria: (a) Determine the equation for the number of bacteria, y, in x hours. b) How many hours will pass before there are 450 bacteria in the
  32. Math (Quadractic function)

    Hi can you help me find the solution for this one? I have the answers at the end but I want to study how did it end with that. Thanks :) The number N of bacteria in a refrigerated food is given by N(T) = 10T^2 - 20T + 600, 1 ≤ T ≤ 20 where T is
  33. Calculus

    A bacteria culture contains 200 cells initially and grows at a rate proportional to its size. After half an hour the population has increased to 360 cells. (a) Find the number of bacteria after t hours. (b) Find the number of bacteria after 4 hours. I
  34. Math

    A colony of bacteria increases according to the law of unihabited growth. a) If the number of bacteria doubles in 5 hours, find the function that gives the number of cells in the culture. I have the answer to this one. It is N=No e ln2/5 (t) b) If there
  35. Algebra 2

    A culture started with 2,000 bacteria. After 6 hours, it grew to 2,200 bacteria. Predict how many bacteria will be present after 12 hours. Round to the nearest whole number.
  36. math

    A biologist grows a culture of bacteria as part of an experiment. At the start of the experiment, there are 75 bacteria in the culture. The biologist observes that the population of bacteria dobules evert 18 minutes. Which of the following equations best
  37. Math

    The doubling period of a bacteria culture is 35 minutes and it starts with 1400 bacteria. How many bacteria will there be after 3 hours? Round your answer to the nearest tenth.
  38. pre calc

    The number N of bacteria in a culture at time t (in hours) grows exponentially according to the function N(t) = 1000e^0.01t. 1.What is the population after 4 hours? 2.When will the number of bacteria reach 1700? 3. When will the number of bacteria double?
  39. Calculus :)

    The number of bacteria in a culture is modeled by n(t)=1550e^(0.24t) (a) The initial number of bacteria is _____ (b) The relative rate of growth of this bacterium population is _____ (c) The number of bacteria after 3 hours is _____ (d) After how many
  40. Algebra

    At noon, Professor Simon has a petri dish with 10,000 cells of Bacteria A. In another petri dish, he has 33,000 cells of Bacteria B. Every hour, Bacteria A grows by 8%. Every hour Bacteria B cells die off, decreasing the number of cells by 6%. After how
  41. Math- PLEASE HELP!!

    At noon, Professor Simon has a petri dish with 10,000 cells of Bacteria A. In another petri dish, he has 33,000 cells of Bacteria B. Every hour, Bacteria A grows by 8%. Every hour Bacteria B cells die off, decreasing the number of cells by 6%. After how
  42. Math NEED HELP URGENT

    At noon, Professor Simon has a petri dish with 10,000 cells of Bacteria A. In another petri dish, he has 33,000 cells of Bacteria B. Every hour, Bacteria A grows by 8%. Every hour Bacteria B cells die off, decreasing the number of cells by 6%. After how
  43. Calculus

    I just need help with one question. A bacteria population starts with 500 bacteria and grows at a rate of r(t) = 548e^(6.5t) bacteria per hour. Determine the number of bacteria after 1 hour. Thank you!
  44. Maths

    The count of bacteria in a certain experiment was increasing at the rate of 2 per hour. Find the bacteria at the end of 2 hours if the count was initially 500000.
  45. Maths Compound Interest

    In a experiment the count of bacteria was increasing at the rate of 2.5% per hour. Initially, the count was 512000.Find the bacteria at the end of 2 hours?
  46. Math

    A culture of bacteria in a petri dish is doubling every hour. If there are 100 bacteria at time t=0, how many bacteria will there be in 12 hours?
  47. Math- Geometric solutions and problems RIA

    A. -x^3 and x^11 ; 3 B. 0.6 and -0.002025; 2 C. x^2,x^6,x^10.... (A sub 20) * sorry for the sub :D but I guess that's already clear? Hehe. D. a^2/2 , a^4/4, a^6/8.... (A sub 10) E. X+1, 2x^2 + 2x, 4x^3 + 4x^2 (A sub 6) F. 32y^2, 16y^2, 8y^2 (A sub 8) *
  48. Precalculus

    a culture starts with 10000 and the number doubles every 40 mins. a. find the function that models the number of bacteria at time t.
  49. Math

    I need some help. A biologist finds that the population of a certian type of bacteria double seach half-hour. An initial culture has 60 bacteria. 1. What is the population after 3 hours? 2. How long will it take for the number of bacteria to reach 983,040?
  50. Physics

    On earth, a certain type of bacteria doubles in number every 24 hours. Two cultures of these bacteria are prepared, each consisting initially of one bacterium. One culture is left on earth and the other is put on a rocket travelling at .866c relative to
  51. Math

    The formula N = 10(4') gives N, the number of bacteria present in a culture after t hours. How many hours does it take for the number of bacteria to grow to 2,560? a. 2 hours b. 3 hours c. 4 hours d. 5 hours The answer is c., but is there another way to
  52. pre calc

    The number N of bacteria in a culture at time t (in hours) grows exponentially according to the function N(t) = 1000e^0.01t When will the number of bacteria reach 1700? I though you would do 1700=1,000^e0.01t and solve for t but i keep getting the wrong
  53. Math

    The doubling function (y = y base0 2^(1/D)) can be used to model exponential growth when the doubling time is D. The bacterium Escherichia coli has a doubling period of 0.32 h. A culture of E. coli starts with 100 bacteria. a) Determine the equation for
  54. CALCULUS

    a bacteria culture grows with a constant per capita growth rate. After 2 hours there are 500 bacteria and after 6 hours the count is 312500, find the initial population and the population after 8 hours
  55. math

    The rate of increase of bacteria in a culture is proportional to the number of bacteria present .if the original number of bacteria double in the two hours, in how many hours will it be five times?
  56. SCIENTIFIC NOTATION

    A lab has two bacteria cultures. Culture A contains 8*10^4 bacteria and culture B contains 4*10^6 bacteria. How do the two cultures compare in size? A. Culture A contains twice as many bacteria as Culture B B. Culture A contains 1/2 as many bacteria as
  57. Algebra

    The number of bacteria in a stagment pond doubles every hour. A farmer sprays it every two hours and kils 3/4 of bacteria immediately. If there are 10,000 live bacteria left after the farmer sprays at noon, how many live bacteria are there at 11 p.m. that
  58. Algebra

    A medical researcher wanted to determine the effect of pH (a measure of alkalinity or acidity, with pure water having a pH of 7) on the growth of a bacteria culture. The table below gives the measurements of different cultures, in thousands of bacteria,
  59. Math

    In a laboratory, a certain culture of bacteria doubles every hour. If there are originally 20 bacteria in the culture, how many are present after 10 hours? 11 hours?
  60. algebra

    Two Questions: 1) A certain radioactive isotope has leaked into a small stream. 100 days later after the leak 10% of the original amount of the substance. Determine the half-life of this radioactive isotope. 2) During a research experiment, it was found
  61. Grade 12 Math-Urgent!

    Bacteria have a doubling time of roughly 10 hours. A normal bacteria starting population would be approximately 10,000 bacteria per ml of fluid...I am not sure if I have done these questions correctly and would like some confirmation before I hand this in
  62. Math

    I'm not sure how to do this question 7. The growth of bacteria in culture can be described by the equation N1 = N0e' where N is the number of bactena at any time t, No is the initial number of bacteria, and k is a constant. The time taken for growth to
  63. math

    The bacteria in a certain culture double every 7.5 hours. The culture has 6,500 bacteria at the start. How many bacteria will the culture contain after 3 hours? Select one:
  64. math

    A medical researcher wanted to determine the effect of pH (a measure of alkalinity or acidity, with pure water having a pH of 7) on the growth of a bacteria culture. The table below gives the measurements of different cultures, in thousands of bacteria,
  65. algebra

    A medical researcher wanted to determine the effect of pH (a measure of alkalinity or acidity, with pure water having a pH of 7) on the growth of a bacteria culture. The table below gives the measurements of different cultures, in thousands of bacteria,
  66. math

    A medical researcher wanted to determine the effect of pH (a measure of alkalinity or acidity, with pure water having a pH of 7) on the growth of a bacteria culture. The table below gives the measurements of different cultures, in thousands of bacteria,
  67. math

    A medical researcher wanted to determine the effect of pH (a measure of alkalinity or acidity, with pure water having a pH of 7) on the growth of a bacteria culture. The table below gives the measurements of different cultures, in thousands of bacteria,
  68. Pre-Calculus

    The population of a particular type of bacteria doubles in number every 12 hours. a)if there are 8 bcteria initially, write an equation that models the number of bacteria present after x 12 hours. b)How many bacteria will be present after 5 days? by using
  69. Math

    To begin a bacteria study, a petri dish had 1500 bacteria cells. Each hour since, the number of cells has increased by 7.1%. Let t be the number of hours since the start of the study. Let y be the number of bacteria cells. Write an exponential function
  70. Pre-Calc (exponential growth)

    A COLONY OF BACTERIA IS GROWN UNDER IDEAL CONDITIONS IN A LAB SO THAT THE POPULATION INCREASES EXPONENTIALLY WITH TIME. At the end of the three hours, there are 10,000 bacteria. At the end of the 5 hours, there are 40,000 bacteria. How many bacteria were
  71. Algebra 1

    I am having trouble with a few questions....Wondering if you could help...My answers have the *** by them..... 1. A lab is growing bacteria in a culture dish. The amount of bacteria in the dish doubles every 3 hours. Initially, there are 500 bacteria in
  72. Math

    A certain type of bacteria is growing at an exponential rate that can be modeled by the equation y=ae^kt, where t represents the number of hours. There are 300 bacteria initially, and 1500 bacteria 5 hours later. Find the rate of growth, k, of the
  73. precalculus

    After 3 hours the number of bacteria in a culture is observed to have doubled. Find the number of bacteria present after 8 hours.
  74. Math

    A certain bacterium divides into 2 bacteria every 20 minutes. If there are four bacteria in the culture now, how many will there be in 4 hours, assuming that no bacteria die?
  75. algebra

    the number of bacteria in a certain population is predicted to increase according to a continuous exponential growth model at a relative rate of 6% per hour. suppose that a sample culture has an initial population of 94 bacteria. find the predicted
  76. Math

    Salmonella bacteria grows rapidly in a nice warm place. If just a few hundred were left on a cutting board when a chicken was cut up, and they get into the potato salad, the population begins compounding. Suppose the number present in the potato salad
  77. algebra

    Suppose that the number of bacteria in a certain population increases according to a continuous exponential growth model, with a growth rate parameter of 11% per hour. Suppose also that a sample culture of 1000 bacteria is obtained from this population.
  78. math

    Five bacteria are placed in a dish and then counted each hour. The first three bacteria counts were 12, 26, 54. If the pattern continues, how many hours after the bacteria were placed in the dish will there be 222 bacteria?
  79. Math

    The number of bacteria in a certain culture T hours from now grows according to A=800(3)^t what will the count be in 3.12 hours from now?
  80. Math

    A bacterial culture starts with 3000 bacteria and increases to 48,000 after 3 hours, find the doubling time:
  81. math

    A type of bacteria doubles in number every 12 hours. After 2 days, there are 48 bacteria. How many bacteria were there at the beginning of the first day. I know the answer is 3, but want to know how it arrived at the number "3"
  82. math

    A lab is growing bacteria in a culture dish. The amount of bacteria in the dish doubles every 3 hours. Initially, there are 500 bacteria in the dish. How many are in the dish after 9 hours? My answer: 4000 -(5)^-1 My answer: -1/5
  83. Algebra

    A lab is growing bacteria in a culture dish. The amount of bacteria in the dish doubles every 3 hours. Initially, there are 500 bacteria in the dish. How many are in the dish after 9 hours? My answer: 4000 -(5)^-1 My answer: -1/5
  84. pre-calculus

    Assume that the number of bacteria follows an exponential growth model: P(t)=P0ekt . The count in the bacteria culture was 900 after 20 minutes and 1600 after 30 minutes. (a) What was the initial size of the culture? (b) Find the population after 80
  85. Math/Pre-calculus

    Assume that the number of bacteria follows an exponential growth model: P(t)=P0e^k/t. The count in the bacteria culture was 400 after 10 minutes and 1500 after 35 minutes. (a) What was the initial size of the culture? (b) Find the population after 85
  86. Algebra

    The number of bacteria in a certain population increases according to an exponential growth model, with a growth rate of 11% per hour. An initial sample is obtained from this population, and after four hours, the sample has grown to 4130 bacteria. Find the
  87. Calculus

    A bacteria population is 3000 at time t = 0 and its rate of growth is 1000 · 6t bacteria per hour after t hours. What is the population after one hour? (Round your answer to the nearest whole number.)
  88. Calculus

    A bacteria population is 3000 at time t = 0 and its rate of growth is 1000 · 6t bacteria per hour after t hours. What is the population after one hour? (Round your answer to the nearest whole number.)
  89. precal

    A petri dish contains only two bacteria. The bacteria divide every half hour. How many bacteria will exist after 3 hours? I thought it'd be 12, but apparently not.
  90. Calculus

    I need some help with this Calculus problem. A bacteria population starts with 500 bacteria and grows at a rate of r(t) = 548e^6.5t bacteria per hour. A. Determine the function P(t) which gives the population at time t. C. How long does it take the initial
  91. Algebra

    In a lab experiement, there is a culture that contains 25 bacteria at 2:00. At 2:15 there are 50 bacteria, At 3:15 there are 800 bacteria. What is the conjecture about the rate at which the bacteria increase?
  92. calculus

    a bacteria pop. grows exponentially. There are 1500 bacteria after 3 hours and 20,000 after 8 hours. ahving trouble finding the initial bacteria pop. thanks for the help In five hours the population get's larger by a factor 13 + 1/3-----> N(t) = N_0 *
  93. precalculas

    the amount of bacteria in a petri dish increased by a percent change of 12% each hour over a period of 15 hours. a. find the growth factor for 1 hour? b. by what total percent did the bacteria change during this 15- hour time period.? c. how long will it
  94. Algebra

    Under ideal conditions, a population of e. coli bacteria can double every 20 minutes. This behavior can be modeled by the exponential function: N(t)=N(lower case 0)(2^0.05t) If the initial number of e. coli bacteria is 5, how many bacteria will be present
  95. Pre-Calculus

    A culture of bacteria obeys the law of unlimited growth. If 500 bacteria are present initially and there are 800 after 1 hour, how many will be present in the cultrue after 5 hours? How long until there are 20,000 bacteria? Hmmm, what is "the law of
  96. Math

    A bacteria culture doubles every 15 minutes. If there are now 500 bacteria in the culture... How many will there be in an hour. N= 500 (2) ^60/15 The answer is 8000 but I am getting 1 x 10^12 what am I doing wrong?
  97. Math

    Suppose that the number of bacteria in a certain population increases according to an exponential growth model. A sample of 2600 bacteria selected from this population reached the size of 2873 bacteria in two and a half hours. Find the continuous growth
  98. Calculus

    Suppose bacteria is growing on a pizza that has been taken out of the refrigerator at a rate that is proportional to the number of bacteria. Suppose there were 50 bacteria when the pizza was removed from the refrigerator and one hour later there were 200
  99. Algebra 2 check my answer please?

    The population of a bacteria in a Petri dish doubles every 16 hours. The population of the bacteria is initially 500 organisms. How long will it take for the population of the bacteria to reach 800? Round your answer to the nearest tenth of an hour. 8.7 h
  100. Algebra 2

    A water sample in a laboratory initially contains 6000 bacteria. The organisms reproduce at a rate of 10% per hour. Find the function that corresponds to this situation. Then predict how long it will take for the population of bacteria to double in number.