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 the dish. How many are in the dish after 9 hours?
A. 4,500 bacteria.
B. 4,000 bacteria.
C. 1,500 bacteria. ***
D. 13,500 bacteria.
2. Determine if the number is written in scientific notation. If not, explain 32 x 10^4.
A. No; it is not written as a power of 10.
B. No; the first factor is not a number between 1 and 10.***
C. Yes; the number is written in scientific notation.
3. Determine if the number is written in scientific notation. If not, explain 2.01 x 10^-5.
A. No; it is not written as a power of 10.
B. No; the first factor is not a number between 1 and 10.***
C. Yes; the number is written in scientific notation.
So is #1 wrong?
amount = 4000(1.04)^3
I get $ 4499.46
#1, they double ever 3 hours, so
after 3 hours you would have 1000
after 6 hours you would have 2000
after 9 hours you would have 4000
or: number = 500(2^(t/3)) , plug in t = 9
#2, correct
#3,
2.01 certainly IS a number between 1 and 10
so C
Another question. An investment account earns 4% per year compounded annually. If the initial investment was $4,000.00, how much is in the account after 3 years? Round your answer to the nearest dollar.
Thanks Reiny.
Thanks for the help, I was struggling on the same ones
Sure, I'd be happy to help you with these questions! Let's go through each question one by one.
1. To solve this problem, we need to determine how many times the amount of bacteria doubles within 9 hours. Since the amount of bacteria doubles every 3 hours, we can divide 9 by 3 to find the number of times it doubles. 9 divided by 3 is 3, so the bacteria doubles 3 times within 9 hours.
Starting with 500 bacteria, we'll double it 3 times:
1st double: 500 bacteria * 2 = 1000 bacteria
2nd double: 1000 bacteria * 2 = 2000 bacteria
3rd double: 2000 bacteria * 2 = 4000 bacteria
After 9 hours, there will be 4000 bacteria in the dish. Therefore, the correct answer is B - 4000 bacteria.
2. The number 32 x 10^4 can be written in scientific notation if 32 is between 1 and 10. In this case, 32 is greater than 10, so it is not in scientific notation. Therefore, the correct answer is B - No, the first factor is not a number between 1 and 10.
3. The number 2.01 x 10^-5 can be written in scientific notation if 2.01 is between 1 and 10. In this case, 2.01 is greater than 10, so it is not in scientific notation. Therefore, the correct answer is B - No, the first factor is not a number between 1 and 10.
I hope this helps! Let me know if you have any further questions.