How long does it take $6,000 to quadruple if it is invested at 9.1% interest compounded annually? a 15.9 years b 17.8 years c 37 years d 222,222.22 years

Question

asked Oct 26, 2022 23.4k views

1 Answer

Fei Qu · Answer 1 · 2022-10-31T13:24:38+0000

Answer:

1. 15.9 years

Explanation:

You must solve this equation:

$6000 \cdot 1.091^n > 24000$

So
1.091^n > 4

Take the log left and right:

$\log 1.091^n > \log 4$

use the log property that you can put the exponent in front:

$n \cdot \log 1.091 > \log 4$

$n > (\log 4)/(\log 1.091)$

n > 15.917