word problems

Question

a woman invested an amount of money at 5% and twice as much at 7%. if her total yearly interest from the two investments is $760. how much was invested at each rate

Answer 1

Principal invested at 5% = P; principal at 7% = 2P.

 

in  1 year, interest earned is, respectively, 0.05(P) + 0.07(2P) = 760.

 

This equation can be solved for P.