



 
Hi, If you can invest money at an annual interest rate of r and you want to accumulate $A in t years then the principal you must invest $P is given by
solve for r, the interest rate. My first thought is to remove the fraction from the expression by multiplying both sides by (1 + rt)
Expand the left side
subtract P from each side
Finally divide each side by Pt
Now try your problem.  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 