In how many days B can finish the work alone? If

A can do in one day three times the work done by B in one day. They together finish 2/5 of the work in 9 days. The number of days by which B can do the work alone is:

  1. 100 days
  2. 30 days
  3. 90 days
  4. 120 days
Monis Rasool Professor Asked on 21st November 2015 in Maths.
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2 Answer(s)

Answer : (3) 90 days

sujeetstar24 Newbie Answered on 21st November 2015.
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Answer: (3) 90 days

Explanation:-
A can do in one day three times the work done by B in one day.
Then, A = 3 B

They together finish 2/5 of the work in 9 days.
Therefore, they together complete the work = 9 x 5/2
= 45/2 days
Then, 3/B + 1/B = 2/45
(3 + 1)/B = 2/45
4/B = 2/45
B = 4 x 45/2
B = 90 days

Then, the number of days by which B can do the work alone is 90 days.

Hence, the answer is (3) 90 days.

Anurag Mishra Professor Answered on 23rd November 2015.
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