.09x+.10(1050-x)=101

Question

 an investor earned a total of $101 at the end of one year by investing $1050 in a money market account of a credit union. Part of this money earned 9% annual simple interest, and the other part earned 10% annual simple interest. How much was invested at each rate?

Answer 1

let x=amount earning 9% interest

let 1050-x=amount earning 10% interest

9%*x + 10%*(1050-x)=101

0.09x+0.1*1050-0.1*x=101

0.09x+105-0.1x=101

-0.01x+105=101

-0.01x=-4

0.01x=4

x=400

1050-400=650

x=$400

y=$650

 

 

Answer 2

.09x+.10y=101

x+y=1050

x=1050-y, .09(1050-y)+.10y=101, 94.5+.01y=101, .01y=6.5, y=650

x=1050-650=400