Mrs Wong retired in 2006, she put a sum of $5000 into a fund that has a constant rate of return of 5 % per annum. Starting in 2006, she withdraws $400 each year and gives the money to her granddaughter as a birthday gift.

a) Denote the amount of money Mrs Wong has at time t years by $x.

b) In which year will the granddaughter receive her last $400?

a) x

b) In the year granddaughter receives last $400,