Brian invests £7500 into his bank account. He receives 6% per year compound interest.
How many years will it take for Brian to have more than £10000?

please i b e g

 5 years

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Work Shown:

The first equation shown is the compound interest formula. I'm assuming that the bank is compounding annually (which means n = 1).

Whenever we have an exponent we want to solve for, we'll involve logs. A good phrase to remember is "If the exponent is in the trees, then log it down".

It takes approximately t = 4.937 years for the £7500 to become £10,000.

Round up to the nearest year to get t = 5 so we ensure that Brian has more than £10,000.