collection of tough problems from G PREP - 5

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A contractor combined x tons of a gravel mixture that contained 10% gravel G, by weight, with y tons of a mixture that contained 2% gravel G, by weight, to produce z tons of a mixture that was 5% gravel G, by weight. What is the value of x?

1. y = 10

2. z = 16
Source: — Data Sufficiency |

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by harsh.champ » Sat Feb 06, 2010 6:26 am
abhasjha wrote:A contractor combined x tons of a gravel mixture that contained 10% gravel G, by weight, with y tons of a mixture that contained 2% gravel G, by weight, to produce z tons of a mixture that was 5% gravel G, by weight. What is the value of x?

1. y = 10

2. z = 16

Both statements required as we have 2 eqns,2 variables.

IMO C.

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by ajith » Sat Feb 06, 2010 7:22 am
abhasjha wrote:A contractor combined x tons of a gravel mixture that contained 10% gravel G, by weight, with y tons of a mixture that contained 2% gravel G, by weight, to produce z tons of a mixture that was 5% gravel G, by weight. What is the value of x?

1. y = 10

2. z = 16
x+y =z

10x+2y = 5z
10x +2y = 5(x+y)
10x+2y = 5x+5y
5x= 3y


1.) Sufficient

5x =3y
x= 3y/5

2) Sufficient
x+y =16
x+5x/3 =16

D
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