Answer:
It would take 4 years for Brian to get more than £10000
Step-by-step explanation:
To work this out, you need to turn the 5% annual interest into a multiplier, which is 1.05
To work out the years taken, start with an estimate, such as 5 years
£8500 x 1.05^5 = £10848.39
Despite this going over £10000, you need to find out the exact year it surpasses the amount, so I lowered the amount of years to 3 and 4 to see which year it goes past £10000
£8500 x 1.05³ = £9839.81
Since after 3 years it hadn't gone past £10000, I knew that the exact year was year 4
£8500 x 1.05^4 = £10331.80
