Question

Brian invests £4000 into his bank account.

He receives 7% per year compound interest.
How many years will it take for Brian to have more than £8000?

Answer 1

10.24 years

Explanation:

The computation of the time period is as follows:

As we know that

Amount = Principal × (1 + rate of interest)^time period

£8000 = £4000 × (1 + 0.07)^time period

£8,000 ÷ £4,000 = 1.07^time period

2 = 1.07^time period

Now apply the log to the both sides

log 2 ÷ log 1.07 = time period

= 10.24 years