11. A and B can together finish a work in 30 days. They worked at it for 20 days and then B left . The remaining work was done by A alone in 20 more days . In how many days can A alone do it .
Answers
Answer :
60 days
Solution :
Given :
• Time taken by A and B together to do a work = 30 days
→ Work done by A and B together in 1 day = 1/30 work
Also ,
It is given that , A and B together worked for 20 days .
Thus ,
Work done by A and B together in 20 days = 20•(1/30) = 2/3 work
Now ,
The remaining work after be left = 1 - 2/3 = (3 - 2)/3 = 1/3 work
Also ,
It is given that , the remaining work done was done by A alone in 20 more days .
Thus ,
Time taken by A to do 1/3 work (the remaining work) = 20 days
→ Time taken by A to do 1 work = 3•20 = 60 days
Hence ,
A can alone do the work in 60 days .
Answer:
60 days
Step-by-step explanation:
(A+B)= 30 days
worked for 20 days together, Beft
remaining done by A in 20 more days
now,
(A+B) 20 days work =1/30×20
= 2/3
remaining work = 1-2/3
=1/3
now 1/3 work is done by A in 20 days
whole work done by A in (20×3) = 60 days