Question

IF A CITYS POP GROWTH RATE IS 7% PER YEAR (COMPOUNDED ANUALLY) , HOW LONG WILL IT TAKE THE CITYS POP TO DOUBLE?

A) 3.86 yrs
B)9.90 yrs
C)10.24 yrs
D) 26 yrs

Answer 1

Let P be the starting population. Then we can use the following equation:
\[2P=P(1+0.07)^{t}\]
which simplifies to
\[2=1.07^{t}\]
Taking natural logs of both sides we get:
\[\ln 2=t\ \ln 1.07\]
from which can can find the value of t:
\[t=\frac{\ln 2}{\ln 1.07}=you\ can\ calculate\]

Answer 2

@bethgrace96 Are you there?

Answer 3

thanks so much!!

Answer 4

You're welcome :)