SOLUTION: How many pounds of extra-lean-hamburger that is 7% fat must be mixed with 30 pounds of hamburger that is 15% fat to obtain a mixture that is 10% fat?
You can put this solution on YOUR website! .07x+.15*30=.10(30+x)
.07x+4.5=3+.10x
.07x-.10x=3-4.5
-.03x=-1.5
x=-1.5/-.03
x=50 pounds of 7% hamburger.
proof:
.07*50+.15*30=.10(30+50)
3.5+4.5=.10*80
8=8