Elena's bread recipe calls for 3 ounces of butter for each 4 cups of flour used. She needs to make 4 times the original recipe. If 12 ounces of butter is used, then how many cups of flour are needed?
Options:
(A) 1
(B) 4
(C) 9
(D) 13
(E) 16
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Number of cups flour needed for 3 ounces of butter = 4
Number of cups flour needed for 1 ounce of butter = 4/3
Number of cups flour needed for 12 ounces of butter = 4/3 * 12 = 16 So the answer is: (E).
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Pipes A and B can fill a cistern in 8 and 24 minutes respectively. They are opened an alternate minutes. Find how many minutes, the cistern shall be full?
Options:
(A) 22
(B) 12
(C) 88
(D) 99
(E) 27
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1/8 + 1/24 = 1/6
6 * 2 = 12 So the answer is: (B).
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For some integer p, p^2 - 5 is divisible by all of the following EXCEPT
Options:
(A) 30
(B) 38
(C) 41
(D) 29
(E) 31
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Hint: p^2-5 (p is an integer) is never multiple of 3 (try to prove this), hence 30 is out. So the answer is: (A).
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