Question

The doubling time of a city's population is 17yrs. how long does it take for the population to quadruple?

I am looking to see how to set this up. I thought 2^2/17 or 2^17/2 but neither works. I know the logical (and answer) but need this set up in the doubling format.

Answer 1

So we know that the doubling time of the population is 17 years right

Answer 2

doubling is similar to saying times 2

Answer 3

So the quadrupling time would probably be the time for the population to grow times 4

Answer 4

So i'm guessing the answer is 17 (the doubling time) multiplied by 2 (to turn it into quadrupling time). so 17 x 2 = 34

Answer 5

I guess I am not sure how to write it out? Is it 2 ^2/17?

Answer 6

maybe it is like 2x = 17 (the given) and 4x= 34 ?

Answer 7

OK- that works for me, but what was confusing was the doubling formula 2^t/Tdouble. Your responses makes sense the formula does not. Thanks!!

Answer 8

Sorry about the formula, i just looked at the question and used logical reasoning I did not have one!

Answer 9

one being a formula

Answer 10

No worries! Logic works for me but this teacher likes everything to the formula.

Answer 11

population=(initial population)*2^(x/17), where x is in years. Then after 17 years you will have double the population and after 34 years you will have 2^2=4 times the population

Answer 12

Thanks!