Question

A can do a work in 14 days and working together A and B can do the same work in 10 days. In
what time can B
alone do the work? एक कार्य को 14 दिनों में कर सकता है और A और B एक साथ कार्य करते
हुए उसी कार्य को 10 दिनों में कर सकते हैं तो B अकेला उस कार्य को कितने समय में कर सकता है?​

Answer 1

A can do the work in 14 days: per day work done by A=1/14

A and Bcan do the work in 10 days: per day work done by A and B=1/10

Work done by B per day=1/10–1/14=7/70-5/70=(7–5)/70=2/70=1/35.

So, B takes 35 days.

Ans.: 35 days

Alternate method:

Numbers involved are 14 and 10; Let us take LCM (70) as number of small units of work.

A can do 70 units in 14 days; so 5 units per day

A and B can do 70 units in 10 days; so 7 units per day

So, B does 2 units per day; B takes 35 days to do 70 units of work (full work).

Ans.: 35 days