Question

Leela invests $500 at 4.5% interest according to the equation mc018-1.jpg, where Vl is the value of the account after t years. Adele invests the same amount of money at the same interest rate, but begins investing two years earlier according to the equation mc018-2.jpg. The total value of Adele’s account is approximately what percent of the total value of Leela’s account at any time, t?

Answer 1

Given:
Leela invests 500 at 4.5%

VI = 500 x 1.045^t

Adele invests 500 at 4.5% but 2 years before Leela invested

Vi = 500 x 1.045^2+t

The total value of Adele’s account is approximately what percent of the total value of Leela’s account at any time, t?

[500 x 1.045^2+t / 500 x 1.045^t] * 100%

1.045² x 100% = 1.092 x 100% = 109.2%

To check: t =1 
Adele: 500 x 1.045^2+1 = 500 x 1.045³ = 570.58
Leela: 500 x 1.045^1 = 500 x 1.045 = 522.50

570.58 / 522.50 = 1.092 
1.092 x 100% = 109.20%

Answer 2

It is D, 109.2

hope that helps