61.
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A works twice as fast as B. If B can complete a work in 12 days independently, the number of days in which A and B can together finish the work in :
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4 days
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6 days
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8 days
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18 days
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Answer: Option A
Explanation:
Ratio of rates of working of A and B = 2 : 1.
So, ratio of times taken = 1 : 2.
B's 1 day's work =
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1
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.
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12
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A's 1 day's work =
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1
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; (2 times of B's work)
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6
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(A + B)'s 1 day's work =
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1
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+
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1
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=
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3
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=
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1
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.
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6
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12
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12
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4
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So, A and B together can finish the work in 4 days.
