Question

A and B can complete a task in 12 days. However. A had to leave a few days before thetask was completed and hence it took 16 days in all to complete the task. If A alone couldcomplete the work in 21 days, how many days before the work getting over did
A leave

Answer 1

Answer:As B leaves 5 days before work, that means for remaining 5 days , A work alone and complete the work.

Step-by-step explanation:

Answer 2

B can alone do the work =

1/ (1/12 -1/21)

1/B .......= 7-4/84=3/84 = 1/28

B......28 DAYS

Let A worked X days

So

Work done by A + Work done by B =1

X/21 +16/28 =1

X/21 = 12/28

X=9

A worked for 9 days means A left work before ( 16-9=) 7 days of completion.