math

posted by George

Suppose y , the number of cases of a disease, is reduced by 11% per year.

(a) If there are initially 10,000 cases, express y as a function of t , the number of years elapsed.

(b) How many cases will there be 6 years from now?

(c) How long does it take to reduce the number of cases to 1000?

  1. MsPi_3.14159265

    a) y =10000(0.11)^t
    b) y = 10000(0.11)^6 and you solve it
    c) 1000 = 10000(0.11)^t and I would divide both sides by 10000 first then either uses exponents or take the log of both sides to solve

  2. Damon

    it is reduced by .11/yr so multiply by 0.89^t

  3. Reiny

    It is reduced by 11% leaving 89%

    so y = 10000(.89)^t

    b) y = 10000(.89)^6

    c)
    10000(.89)^t = 1000
    .89^t = .1
    t log .89 = log .1
    t = -1/-.0506099.. = appr 19.76 years

  4. MsPi_3.14159265

    Thanks math gang! Time for a cup of afternoon tea. I was doing the math in my head and .89 didn't feel just right. LOL! Thanks again for the correction : )

Respond to this Question

First Name

Your Answer

Similar Questions

  1. statitics

    E. Coli outbreak. Outbreaks of E. coli have occurred at a rate of 2.5 per 100,000. Assume this rate represents the mean for the number of outbreaks (as a Poisson random variable). a. What is the probability that at most five cases …
  2. Calculus

    a local office supply store has an annual demand for 50,000 cases of photocopier paper per year. it costs $2 per year to store a case of photocopier paper, and it costs $50 to place an order. Find the optimum number of cases of photocopier …
  3. Epidemiology

    How do you calculate the disease frequency rate in these problems 1. The cumulative incidence rate in a population of 100,000 people where 9 new cases of disease were reported within 1 year 2. The prevalence of a chronic disease on …
  4. math

    The number of cases for a disease has reduced by half every 10 years: 1970 - 21,168 1980 - 10,584 1990 - 5,292 Assume N is the number of reported cases t years after 1970. Which is a good model for N(t)?
  5. college algebra

    1984-1994 the equation the number of aids cases can be modeled by the equation C(x)=3034x^2+14,018x+6400 X represents years after 1984 estimate the year when 200,000 aids cases had been diagnosed.
  6. college algebra

    1984-1994 the equation the number of aids cases can be modeled by the equation C(x)=3034x^2+14,018x+6400 X represents years after 1984 estimate the year when 200,000 aids cases had been diagnosed.
  7. mat-119

    Greg Tobin sells bottled water. He has found that the average amount of time he spends with each customer is related to his weekly sales volume by he function f(x)=x(60-x), where x is the number of minutes per customer and f(x) is …
  8. statistics

    A quality supervisor for a factory that makes cell phone cases examines a sample of 46 cases. She finds that 8 cases are the wrong size. Which is the best prediction of the number of cases that will be the wrong size in a shipment …
  9. Statistics

    Episodes of dehydration are common at outdoors music festivals. At a particular large annual event, a first aid team has recorded over the years 85 cases on average per day. In 2018, during a weekend they observe 78, 86, 79, and 81 …
  10. Statistics

    Episodes of dehydration are common at outdoors music festivals. At a particular large annual event, a first aid team has recorded over the years 85 cases on average per day. In 2018, during a weekend they observe 78, 86, 79, and 81 …

More Similar Questions