Question

Tina wants to save money for school. Tina invests $400 in an account that pays an interest rate of 7.5%.

How many years will it take for the account to reach $8,500? Round your answer to the nearest hundredth. Please show me the work.

Answer 1

Here's the given:
P=$400
i=7.5%
A=$8500

The formula used for this problem is:
A = P(1+i)^t

Manipulating the equation to arrive at t, we have:
t = ln(A/P) / ln(1+i)

Plugging in values:
t = ln($8500/$400) / ln(1+0.075)
t = 42.26 years