Question 70527
.07x+.05(x-4000)=520 [7% of x plus 5% of (4000-x)]=520 interest
.07x+.05x-200=520
.12x=520+200
.12x=720
x=720/.12
x=6000 invested @ 7%
6000-4000=2000 invested @ 5%
proof
.07*6000+.05*2000=520
420+100=520
520=520