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by Strongt » Mon May 30, 2011 5:20 am
A is twice as good a workman as B and together they finish a set of work in 14 days. The number of days taken by A alone to finish the work

1)11
2)21
3)28
4)30


Not sure what the answer is.

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by cans » Mon May 30, 2011 5:31 am
IMO B
Suppose A takes x days, and thus B takes 2x days.
Both A & B complete in 1/(1/x+1/2x) = 2x/3 = 14
=> x=21 days
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by cans » Mon May 30, 2011 5:32 am
IMO B
Suppose A takes x days, and thus B takes 2x days.
Both A & B complete in 1/(1/x+1/2x) = 2x/3 = 14
=> x=21 days
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by GMATGuruNY » Mon May 30, 2011 5:34 am
Strongt wrote:A is twice as good a workman as B and together they finish a set of work in 14 days. The number of days taken by A alone to finish the work

1)11
2)21
3)28
4)30


Not sure what the answer is.

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Let rate for A = 2 units per day and rate for B = 1 unit per day.
Combined rate for A and B = 2+1 = 3 units per day.
Work completed in 14 days = r*t = 3*14 = 42 units.
Time for A alone to produce 42 units = w/r = 42/2 = 21 days.

The correct answer is B.
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by Anurag@Gurome » Mon May 30, 2011 5:35 am
Strongt wrote:A is twice as good a workman as B and together they finish a set of work in 14 days. The number of days taken by A alone to finish the work

1)11
2)21
3)28
4)30

Not sure what the answer is.

Source GmatClub
Let A takes x days to finish the work. Then B takes 2x days to finish the work.
So, 1/x + 1/2x = 1/14
3/2x = 1/14
x = 21 days

The correct answer is 2.
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