# Thread: another problem i am working on

1. ## another problem i am working on

the formula A=P(1+(r/n))^nt is used to compute the value of an investment with interest compounded monthly if th annual interest rate: r=6.25% answer the following questions

if 15,000 is invested originally what is the value of the investment after 5 years

how long will it take for an investment to triple in value

2. Originally Posted by math321
the formula A=P(1+(r/n))^nt is used to compute the value of an investment with interest compounded monthly if th annual interest rate: r=6.25% answer the following questions
Actually that is the formula for interest compounded n times a year. For "compounded monthly", n= 12.

if 15,000 is invested originally what is the value of the investment after 5 years
Just evaluate the formula: $A= (15000)\left(1+ \frac{.0625}{12}\right)^{(12)(5)}$

how long will it take for an investment to triple in value
So A= 3P. Solve $3P= P\left(1+ \frac{.0625}{12}\right)^{(12)t}$ for t. An obvious first step is to cancel the "P"s. Then take a logarithm of both sides.