ardz24 wrote:How many gallons of water should be added to make the average value of the mixture $480 per gallon.
(1) 5 gallons of Milk type I is mixed with 6 gallons of Milk type II.
(2) Milk of type I is $600 per gallon and the cost of type II Milk is 90% of the cost of Milk of type I.
What's the best way to determine which statement is sufficient?
The question is not clear about the cost of water. Since this is DS question, we cannot necessarily assume this. If we assume that water is free, then the answer is C.
(1) 5 gallons of Milk type I is mixed with 6 gallons of Milk type II.
Clearly isufficient as we do not know the costs of the Milk types.
(2) Milk of type I is $600 per gallon and the cost of type II Milk is 90% of the cost of Milk of type I.
Clearly isufficient as we do not know the volumes of the Milk types.
(1) and (2) together
From (2), we have cost per gallon of type II Milk = 90% of $600 = $540.
Total cost of the mixture before mixing water = 5*600 + 6*540 = $6240
Say x gallons of free water is added, thus the average cost of the mixutre = 6240 / (11 + x)
=> 6240 / (11 + x) = 480
It's a linear equation, we can get the unque value of x. Sufficient.
The correct answer:
C
Hope this helps!
-Jay
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