Question

Rachel deposited $5,960.32 into a savings account with an interest rate of 4.2% compounded twice a year. About how long will it take for the account to be worth $9,000? (3 points) a 21 years, 1 month b 18 years, 0 months c 19 years, 10 months d 9 years, 11 months

Answer 1

d 9 years, 11 months

Explanation:

Rachel deposited $5,960.32 into a savings account with an interest rate of 4.2% compounded twice a year.

P = $5,960.32

Rate = 4.2%

Number of years = x

Final amount=$9000

Number of times compounded= x/2

A= p(1+r/n)^(nt)

9000= 5960.32(1+(0.042*2)/x)^(x/2 *x)

9000= 5960.32(1+0.084/x)^x²/2

2(9000/5960.32)=(1+0.084/x)^x²

3.019972=((x+0.084)/x)^x²

On trial an error

The value of x is found to be approximately 9 year, 11 months