Question

A sample in a laboratory starts with 8 bacteria. The bacteria grow at a rate of 3.2% every hour. How many hours until the sample has grown to 140,000

bacteria? (Round to the nearest whole number)
A 46
B 3
C) 305
D 133

Answer 1

probably C

Explanation:

The question can be written as:

8 * 1.032^n = 140 000, this can be rearranged to

140 000/8 = 17500 = 1.032^n

now we need to find n, we could do this manually with a calculator, but an easier method is to use
`\log_x(y)`

example of log

2^3 = 8

log2 (8) = 3

log1.032 (17500) = 310.17