Henry invest £8000 in youtube at a compound interest rate of 2% per year. He wants to earn more than £500 interest. Work out the least time, in whole years, that this would take?

Each year his money will increase by 2%, meaning he will get 102% of his money from the previous year. This can be written as 1.02. After n years, he will make 8000 x 1.02 ⁿ. Calculate this for 1, 2, 3, 4... years up until he has made £500: 8000x1.02¹ = 8160 (he has made £160), 8000x1.02²= 8323.2 (he has made £323.20), 8000x1.02³ = 8489.66 (he has made £489.66), 8000x1.02⁴ = 8659.46 (he has made £659.46). Thus he must invest for 4 years.