Question

A and B together can complete a job in 12 days. A alone can complete it in 24 days. Find the time taken by B to
complete it.​

Answer 1

Answer:

30 days

Explanation:

can do a work in = 20 days

Let B can do the work in =X days

Both A and B can do the work in = 1/12 days

Therefore 1/20 + 1/X= 1/12

So 12 (X+20) = 20 X;

So 8X= 240 ; X= 30.

Therefore “B” can do the work alone in 30 - days.

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Another Simple Method:

In 12- days A- can complete= 12/20= 3/5- part of the work.

So in 12- days B- can complete (1–3/5) = 2/5- part of the work.

So complete work can be done by B- alone in 12÷ (2/5)= 12 x5/2= 30- days.

Answer 2

Answer:

30 days

Explanation:

A can do a work in 20 days .

Let B can do the work in x days .

Both A and B can do the woke in = 1/12 days .

Therefore 1/20+ 1/x = 1/12

so 12 ( x+20) = 20x

so 8x = 240 ; x = 30

Therefore " B " can da the work alone in 30 days .