milk and water :)

[divya23]

3 grades of milk are 1%,2%,3% fat by volume.if x gallons of 1 percent,y gallon of 2 percent and z of 3 are mixed to give x+y+z gallons of a 1.5 percent grade wat is x in terms of y n z?
1. y +3z
2.y+z/4
3.24+3z
4.3y+z
5.3y+4.5z

OA = A

[cans]

x gallons of 1% means .01x fat
y gallons of 2% means .02y
z gallons of 3% means .03z
total = .01x+.02y+.03z = .015*(x+y+z)
thus x + 2y+ 3z = 1.5x + 1.5y + 1.5z
x = y + 3z
IMO A

[GMATGuruNY]

3 grades of milk are 1%,2%,3% fat by volume.if x gallons of 1 percent,y gallon of 2 percent and z of 3 are mixed to give x+y+z gallons of a 1.5 percent grade wat is x in terms of y n z?
a. y + 3z
b. (y + z)/4
c. 2y + 3z
d. 3y + z
e. 3y + 4.5z

OA = A

We can plug in values.
If equal amounts of X=1% and Y=2% are combined, the resulting mixture will be (1+2)/2 = 1.5% fat.
Let x=2, y=2, z=0.
The question asks for the value of x=2. This is our target.

Now we plug y=2 and z=0 into the answers to see which yields our target of 2.

Only answer choice A works:
y+3z = 2+(3*0) = 2.

The correct answer is A.