Question

If you invest $1500 at a rate of 7% per year, how many years will it take to earn at least $1050 in interest?

Answer 1

`8`

Explanation:

The formula is compound interest rate:
`P(1+ r/n)^(n*t) = A`
`P` is Principal amount;
`r` is interest rate;
`n` is number of compounds per year/months and etc.
`t` is time in years/months and etc.
`A` is last Amount

So
`1500*(1+0.07/365)^(365*t)=(1500+1050)`

`1500*(1+0.07/365)^(365*t)=2550`

It is hard to calculate. That is why you can apply for Google. There is the compound interest rate calculator on the web.

As a result, the answer or `t` is `8`
It means that you have to wait for `8` years in order to earn at least extra `$1050`.