求助怕热拍数学题

fionafan518

Three grades of milk are 1 percent, 2 percent, and 3 percent fat by volume.  If x gallons of the 1 percent grade, y gallons of the 2 percent grade, and z gallons of the 3 percent grade are mixed to give x + y + z gallons of a 1.5 percent grade, what is x in terms of y and z ?

schighness

0.01x+0.02y+0.03z/(x+y+z)=0.015
0.01x+0.02y+0.03z=0.015x+0.015y+0.015z
0.005x=0.005y+0.015z
x=y+3z