How 20 came ?? please anyone explain me see the pic attached.
Q) a can do a piece of work in 4 days and B in 5 days how long will they take to do the same work when working together.
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LCM OF 4 AND 5,..........,.....
Answered by
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Answer:
its by LCM
LCM is a common number between two numbers
multiple of 5 =4,8,12,16,20
multiple of 5=5,10,15,20
here 20 is common so we take LCM as 20
It is given that
A can do a piece of work in 4 days B can do the same work in 5 days
A's one day's work = 1/4
B's one day's work = 1/5
A and B both one-day work =
1/4 + 1/5 = 5+4/20
=
9/20
A and B two day's work =
9/20×2
=9/10
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