Milk Problem

This topic has expert replies
Senior | Next Rank: 100 Posts
Posts: 38
Joined: Fri Aug 17, 2012 11:28 am
Thanked: 2 times

Milk Problem

by avada » Sat Sep 08, 2012 2:01 pm
This is from a Gmac Practice test from mba.com

3 grades of milk are mixed together to produce 1.5 percent. If x gallong 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?

1. y+3z
2.(Y+Z)/4
3. 2y+3z
4. 3Y+Z
5. 3y +4.5Z


Answer= 1.

User avatar
Master | Next Rank: 500 Posts
Posts: 167
Joined: Fri Mar 09, 2012 8:35 pm
Thanked: 39 times
Followed by:3 members

by adthedaddy » Sat Sep 08, 2012 2:25 pm
There are some words you've missed in the question. Hope you're referring to this question only - https://www.beatthegmat.com/three-grades ... 13867.html

I would solve it this way -

1%x + 2%y + 3%z = 1.5%(x+y+z)
=> x+2y+3z = 1.5x + 1.5y + 1.5z
=> 0.5x = 0.5y + 1.5z
=> x=y+3z
First Option
"Your time is limited, so don't waste it living someone else's life. Don't be trapped by dogma - which is living with the results of other people's thinking. Don't let the noise of others' opinions drown out your own inner voice. And most important, have the courage to follow your heart and intuition. They somehow already know what you truly want to become. Everything else is secondary" - Steve Jobs

User avatar
Legendary Member
Posts: 588
Joined: Sun Oct 16, 2011 9:42 am
Location: New Delhi, India
Thanked: 130 times
Followed by:9 members
GMAT Score:720

by rijul007 » Sat Sep 08, 2012 2:30 pm
(1% of x gallon) + (2% of y gallons) + (3% of z gallons) = 1.5% of (x+y+z) gallons
((x/100)+(2y/100)+(3z/100))/(x+y+z) = 1.5/100

(x+2y+3z)/(x+y+z) = 1.5
x+2y+3z = 1.5x+1.5y+1.5z
0.5y+1.5z = 0.5x
x = y+3z

Option A