Question

A can do 1/4 the work in 5 days , B can do 1/5 of the work in 6 days . how long would both of them take to complete the work if they worked togather

Answer 1

A - >1/4 = 5 days so days required for completing full work = 5*4 = 20 days

B - > 1/5 = 6 days so days required for completing full work = 6*5 = 30 days

Let the total number of days to complete the work together be x

So work done by them in one day together is = 1/x
So work done by A = 1/20 in one day 
So work done by B = 1/30 in one day

So,

1/20 + 1/30 = 1/x
30+20/30*20 = 1/x
50/600 = 1/x
5/60 = 1/x
1/12 = 1/x

so x = 12 days.

Therefore ot would take 12 days for them to complete that work together.

Hope it helps!!
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