Question

About how many years will it take for $4000 to double at a simple interest rate of 9%

And please explain. Thank you!!!

Answer 1

about 11 years

Explanation:

we know that

The simple interest formula is equal to

`A=P(1+rt)`

where

A is the Final Investment Value

P is the Principal amount of money to be invested

r is the rate of interest

t is Number of Time Periods

in this problem we have

`t=?\ years\\ P=\$4,000\\ A=\$8,000\\r=9\%=9/100=0.09`

substitute in the formula above

`8,000=4,000(1+0.09t)`

solve for r

`2=(1+0.09t)`

`0.09t=2-1`

`0.09t=1`

`t=11.1\ years`