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Bunuel
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B is twice efficient as A and A can do a piece of work in 15 days. Thu Aug 08, 2024 2:45 pm
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55% (hard)

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70% (02:32) correct 30% (02:48) wrong based on 185 sessions

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­B is twice efficient as A and A can do a piece of work in 15 days. A started the work and after a few days B joined him. They completed the work in 11 days, from the starting. For how many days did they work together?

A. 2
B. 3
C. 5
D. 6
E. 7­
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A
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B is twice efficient as A and A can do a piece of work in 15 days. Thu Aug 08, 2024 4:13 pm
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Bunuel
­B is twice efficient as A and A can do a piece of work in 15 days. A started the work and after a few days B joined him. They completed the work in 11 days, from the starting. For how many days did they work together?

A. 2
B. 3
C. 5
D. 6
E. 7­
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­Assuming efficiencies as a and b for both A and B resepctively.
­B is twice efficient as A and A can do a piece of work in 15 days. = b = 2a
Total amount of work = 15a
A started the work and after a few days B joined him. They completed the work in 11 days, from the starting.
So, 11 days A was working
Amount of work done by a + amount of work done by b = 15a
11a + amount of work done by b = 15a
lets assume b joined for x days and as we know b=2a
2ax = 15a - 11a = 4a
x=2
So they work for 2 days together
Answer is Option A.
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B is twice efficient as A and A can do a piece of work in 15 days. Fri Aug 09, 2024 6:31 am
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Rate of A = 1/15


Rate of B = 2/15


1/15(11 - x ) + (1/15 + 2/15 )x = 1


11 - x + 3x = 15


2x = 4

x = 2

Answer A

Adewale Fasipe, GMAT quant instructor, Lagos Nigeria.
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B is twice efficient as A and A can do a piece of work in 15 days. Sat Nov 15, 2025 7:14 am
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Rate of A = 1/15
Rate of B = 2/15

Days worked by A = 11
Days worked by B = 11-x

No. of days A&B worked together = 11-x

WD by A = 11/15
WD by B = 22-2x/15

11/15 + 22-2x/15 = 1
33 - 2x = 15
18/2 = x
x = 9

No. of days A&B worked together = 11-x = 11-9 = 2

Option A

Bunuel
­B is twice efficient as A and A can do a piece of work in 15 days. A started the work and after a few days B joined him. They completed the work in 11 days, from the starting. For how many days did they work together?

A. 2
B. 3
C. 5
D. 6
E. 7­
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Bunuel
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