Thread: Having trouble

1)An old coin was worth 50 cents originally and has been growing exponentially in value by 15% every year. Predict the coin's value after 3.5 years


2) Two investments are made. In one, $2500 is invested at 5% compounded annually. In other, $2000 is invested at 6% compounded annually. When will the investments have the same value?

#1:

Since the coin increases $0.15/yr, then after the first year it is worth $0.575.

Using the forumula

we get the two equations

and



using substitution we get the equation



taking ln of both sides

using log properties

isolating t