Question

What was the interest rate if your balance On an investment of $555 at the end of six years is $821.40?

Answer 1

The interest rate is 8% simple interest.

Explanation:

Let the investment of $555 is getting r% simple interest for 6 years to become the balance of $821.4.

So, from the equation of the simple interest we can write

`821.4 = 555(1 + (6r)/(100))`

⇒
`(1 + (6r)/(100)) = 1.48`

⇒
`(6r)/(100) = 0.48`

⇒ r = 8%

Therefore, the interest rate is 8% simple interest. ( Answer )