The formula below gives T, the approximate time in years it takes a population to double if the annual growth rate is r percent.
According to this formula, about how long will it take a population to double if the annual growth rate is 4.6%?
A. 24 years
B. 21 years
C. 15 years
D. 18 years

Question

The formula below gives T, the approximate time in years it takes a population to double if the annual growth rate is r percent. 
According to this formula, about how long will it take a population to double if the annual growth rate is 4.6%?
 		A.	24 years
 		B.	21 years
 		C.	15 years
 		D.	18 years

anonymous · Answer

T = 70/r 
if you replace r with 4.6 it equals 15 years.