Posted by chanell on Friday, October 14, 2011 at 2:05pm.
invest x at 4%, y at 8%
x + y = 40000
.04x + .08y = 2720
.08x + .08y = 3200
.04x + .08y = 2720
now subtract:
.04x = 480
x = 12000
y = 28000
.04*12000 + .08*28000 = 480 + 2240 = 2720
x + y = 40,000
.04x + 0.08y = 2,720
x = 40,000 - y
.04(40,000 - y) + 0.08y = 2,720
1,600 - .04y + 0.08y = 2,720
1,600 + 0.04y = 2,720
0.04y = 1,120
y = 28,000
x = 40,000 - 28,000
x = 12,000
y = 28,000