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by rahul.s » Sun Jan 31, 2010 2:57 am
In a certain art museum, 15 percent of the collection consists of oil paintings from the Impressionist period. If 40 percent of the oil paintings in the museum's collection are not from the Impressionist period, what percent of the museum's collection consists of oil paintings?

A) 20 %
B) 25 %
C) 37.5 %
D) 62.5 %
E) 80 %

OA: B

i got the solution right, but i'd like to know different approaches
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by sars72 » Sun Jan 31, 2010 3:04 am
Taking total no. of collections, c, to equal 100

--> No. of oil paintings from Impressionist persiond, I, = 0.15c = 15

40 % of Oil Paintings, o, are not from Impressioninst period (n) -> 0.4o = n

Question -> What percent of o make up c?

--> 0.15c = 0.6o

--> c/4 = o

Therefore oil paintings, o, make up 1/4 i.e. 25% of the museum's collections
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by bhumika.k.shah » Sun Jan 31, 2010 3:08 am
N = 100 = total # of paintings.

40 = Paintings from not from I period
60 = Paintings from I period

Of 100, 15% are from oil collection - 15 = also from I period

Therefore,
15/60 * 100 = 25%

Hence B :)
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by papgust » Sun Jan 31, 2010 5:09 am
This could also be solved using a double-matrix.
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