A paint store makes peach paint according to the formula ab

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formula

white : 3/5 gallon
red : 1/4 gallon
yellow :1/3 gallon

A paint store makes peach paint according to the formula above. The numbers of gallons of white and yellow paint used in a batch of peach paint are always each an integer. If the store owner wants to make the smallest batch of peach paint possible, how many gallons of red are needed?

A) 1/4
(B) 1
(C) 3(3/4)
(D) 5
(E) 9
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by Anurag@Gurome » Mon Jul 09, 2012 10:58 am
W:R:Y = (3/5):(1/4):(1/3)

To make the ratio of white and yellow an integer, we need to multiply each term in the ratio by a multiple of 3 and 5. And as we need to make the smallest batch possible, we will multiply by the LCM of 3 and 5 = 15

Hence, W:R:Y = 9:(15/4):5

Hence, 15/4 = 3 and 3/4 gallons of red paint is required.

The correct answer is C.
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by alex.gellatly » Mon Jul 09, 2012 10:06 pm
gmatter2012 wrote:formula

white : 3/5 gallon
red : 1/4 gallon
yellow :1/3 gallon

A paint store makes peach paint according to the formula above. The numbers of gallons of white and yellow paint used in a batch of peach paint are always each an integer. If the store owner wants to make the smallest batch of peach paint possible, how many gallons of red are needed?

A) 1/4
(B) 1
(C) 3(3/4)
(D) 5
(E) 9
To make White and Yellow both integers the total amount of paint (in gallons) must be a multiple of 5 and 3. The least amount of paint used is thus 3*5=15 gallons. So White is (3/5)*15 = 9, Red is (1/4)*15 = 15/4 or 3 and 3/4, and Yellow is (1/3)*15 = 5. So answer should be C.

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by gmatter2012 » Tue Jul 10, 2012 2:28 am
Now this has become very clear, this question was solved in a very peculiar way , in its source .

but after seeing the explanation here, its clear