Someone invests £1000 in an account offering an interest rate of 5% each year. How many years will it take to get £1500.
I used the equation Sn=n/2[2a+(n-1)d] and I have made d=1.05, a=1000 and Sn=1500.
I got a quadratic equation which came out at about 1.5 and -2000 which can't be right.
So have I made a glaring error or used the wrong equation?
Any help/advice would be great.
Arithmetic Progression Difficulty Watch
- Thread Starter
- 21-06-2016 12:16
- Study Helper
- 21-06-2016 14:36