Question

Peggy deposited $83 into a savings account. What interest rate will cause her money to double in approximately 42 years? 1.7% (Apex)

Answer 1

Answer: A 1.7%

Explanation:

A P E X is garbo

Answer 2

Answer: Yes, the approximate annual rate is 1.7%

Explanation:

Here, the principal amount, P = $ 83,

Time, t = 42 years

Amount after 42 years, A = $ 166

Let the annual rate of interest = r %,

By the compound interest formula,

We can write,

`P(1+(r)/(100))^t = A`

`83(1+0.01r)^(42)=166`

`(1+0.01r)^(42)=2`

`1+0.01r=1.01664043939`

`0.01r=0.01664043939`

`r=1.664043939\%\approx 1.7\%`

⇒ The annual rate of interest = 1.7% ( Approx )