Elie wants to double her savings of £8000 by investing her money for 20 years.
what interest rate does she need to look for?
Give your answer to 1 d. p.

5 years ago Jez invested £30000 at a compound interest rate of 15% p. a.
15 years ago, Kat invested £30000 at a compound interest rate of 5% p. a.
Whose investment is worth more now and by how much?
Give your answer to the nearest £