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Bunuel
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Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
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Divyanshu14
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GRE 1: Q165 V160
GRE 1: Q165 V160
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rajatchopra1994
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Explanation:

Vessel 1 per litre milk price which contains 220L milk = x, total price = 220x
Vessel 2 per litre milk price which contains 180L milk = y, total price = 180y
S Litre milk removed from each vessel
So, Price of vessel 1 = {(220 - S)x + S*y}/ 220
Price of vessel 2 = {(180 - S)y + S*x}/ 180
Price of vessel 1 = Price of vessel 2
{(220 - S)x + S*y}/ 220 = {(180 - S)y + S*x}/ 180
{(220 - S)x + S*y}/11 = {(180 - S)y + S*x}/9
9*(220x - S*x + S*y = 11*(180y - S*y + S*x}
1980x - 9S*x + 9S*y = 1980y - 11S*y + 11S*x
1980*(x-y) = 20(S*x - S*y)
1980 (x - y) = 20S(x - y)
1980 = 20S
S = 99
IMO-C
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carouselambra
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I think this is a beautiful question!
However, I tend to have an affinity towards using/plugging numbers to derive an answer instead of algebra.

Can someone please help me with an example of the same?
Thanks in advance!
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I don't know why no one is using allegation
Here's a simple way
Let

Applying allegation

a-P/P-b = x/220-x......eqn 1
a-P/P-b = 180-x/x......eqn2
Equating both the equations, we get
x/220-x = 180-x/x
x^2 = (220-x)(180-x)
only 99 satisfies this equation
Hence, C
Bunuel
There are two vessels of milk of different prices, per litre, with the volume of 220 litres and 180 litres, respectively. Equal amounts of milk were poured off simultaneously from the two vessels and the milk poured off from the first vessel was poured into the second vessel and milk poured off from the second vessel was poured into the first vessel. Then the price of milk in both the vessels, per litre, becomes the same. How much milk was poured from one vessel into the other?

A. 80
B. 90
C. 99
D. 160
E. Cannot be determined


Are You Up For the Challenge: 700 Level Questions

There are 2 drums of oil of different prices, their volume being 220 gallons and 180 gallons. Equal quantities are drawn off from the 2 drums. The oil drawn from the first drum is poured into the second drum, and the oil drawn from the second drum is poured into the first drum. Then the price of oil per gallon in both drums becomes equal. How much is drawn from each drum?
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