Voldemort has a savings account containing $10,000. Interest accumulates so that every five years, the amount of money in that account grows to 11/10 of its amount at the beginning of the five years. How much money is in that account after twenty years, given that no money is put into or taken out of the account?
EDIT: NEVER MIND, GOT IT.
At 5 years it will be 11/10 * 10000 then at 10 years it will be 11/10 * 11/10 * 10000
Sooooo at TWENTY years = 11/10 * 11/10 * 11/10 * 11/10 * 10000 = (11/10)4 * 10000 = $ 14641.