Request assistance with this GMAT Prep Quant Probem

[rohitsujirnayak]

Request your assistance with this GMAT Prep Quant Problem

Source: GMAT Prep software


Three Grades of Milk are 1%, 2% 3% fat by volume. If x gallons of 1%, y gallons of 2% and z gallons of 3% are mixed to give x+y+z gallons of 1.5%, what is x in terms of y and z.

I used the plugging in method to solve this problem.

Why is the answer to this problem y+3z and not 3y + z? - When i plug in numbers, 400g (x) , 100g (y) and 100g (z) when mixed gives x+y+z at 1.5%

If i follow this line of reasoning- y+3z or 3y+z - both could be right.


Please help :)

Rohit

[stucked]

Hi Rohit,

I am not sure if number picking strategy would be a wise move. According to question the equation becomes:
1(x)+2(y)+3(z)=1.50(x+y+Z)
[I have eliminated % age sign for simplification]
thus,
x+2y+3z=1.5x+1.5y+1.5z
0.5x=0.5y+1.5z
x=(0.5y+1.5z)/0.5
x=(0.5y/0.5)+(1.5z/0.5)
x=y+3z
[correct answer]

hope it helps

[RonPurewal]

Please search the forum before you post. Thanks. (Virtually every problem in the GMAT PREP free software already has a thread on the forum.)

three-grades-of-milk-are-1-percent-2-percent-and-3-percent-t3692.html