Question

Jocelyn invests $1,600 in an account that earns 2.5% annual interest. Marcus invests $400 in an account that earns 5.4% annual interest. Find when the value of Marcus's investment equals the value of Jocelyn's investment and find the common value of the investments at that time. If necessary, enter the year to the nearest tenth and the value to the nearest cent.

Answer 1

Total = Principal * (1 + rate) ^ years

We have to solve this for years:

Years = {log(total) -log(Principal)} ÷ log(1 + rate)

Jocelyn: Years = {log(total) -log(1,600)} ÷ log(1.025)

Marcus: Years = {log(total) -log(400)} ÷ log(1.054)

We know the years must be equal but we won't know the total so we'll call that "x".

[log(x) -log(1,600)] ÷ log(1.025) = [log(x) -log(400)] ÷ log(1.054)

EDITED TO ADD

Time is about 49 Years 8 Months and total is about 5,454.00

We know the years must be equal

Explanation: