He was 21 in 1980,
There are twelve years in between them all so you subtract 36 from 78 and since he was double as old as Nancy, and Manual was the same age as her, you would divide 42 into two parts, Ric and the 10.5 year olds, and Ric would be 21 in 1980.
The general equation for exponential growth can be written as:

where r is the growth rate.
Plugging in the given values, we get:

Therefore

giving
![1+r= \sqrt[3]{1.1} =1.0323](https://tex.z-dn.net/?f=1%2Br%3D%20%5Csqrt%5B3%5D%7B1.1%7D%20%3D1.0323)
The predicted number of bacteria after 17 hours is given by:
The answer is C. If you have any questions then leave a comment. Good luck!
B is your awnser! sorry if im wrong my calc shows its without a - symbol