VeritasPrepKarishma wrote:
rxs0005 wrote:
Jug contains water and orange juice in the ratio 5:7 . another jug contains water and orange juice in ratio 7 : 2 . In what proportion should these 2 liquids be mixed to give a water and orange juice in ratio 3 : 4
4 : 5
85 : 3
88 : 3
2 : 3
87 : 7
4 : 5
85 : 3
88 : 3
2 : 3
87 : 7
In such questions focus on one thing - either water or orange juice. Let's work with water
Jug1 - Water concentration is 5/12
Jug2 - Water concentration is 7/9
Mixture - Water concentration is 3/7
Now, \frac{w1}{w2} = \frac{\frac{7}{9} - \frac{3}{7}}{\frac{3}{7} - \frac{5}{12}} = \frac{88}{3}
A detailed explanation of the concept used above is given here:
http://www.veritasprep.com/blog/2011/03 ... -averages/
This is a general concept and you can use it directly if applicable.