Practice!

Sample Problem

You have invested $3500 in a manufacturing company that produces a brand new cleaning device, allowing them to clean all the jail cells in Asia and in Europe in just one hour. You receive 4.75% interest, compounded continuously. How long will it take your money to triple? Round your answer to the nearest whole number.

years

Solution

A=Pert

A=3500e0.0475t

3500*3=10500

10500=3500e0.0475t

3=e0.0475t

ln 3= ln e0.0475t

ln 3=0.0475t * ln(e)

ln 3/ln e=0.0475t

ln 3/1=0.0475t

ln 3/0.0475=t≈23 years