A and B together can finish a work in 30 days. They worked for it for 20 days and then B left the work. The remaining work was done by A alone in 20 days more. In how many days can A alone finish the work?
A) 48 days B) 50 days C) 54 days D) 60 days
Answers
Answer:
answer D) 60 days
Step-by-step explanation:
Work done by A and B together in 1 day = 1/30
A + B = 1/30 => B = 1/30 - A
A and B worked together for 20 days + A alone completed the remaining work in 20 days = whole work
(A + B )20 + (A )20 = 1
40A + 20( 1/30 – A) = 1
20A = 1 – 20/30
20A = 10/30
A = 1/60
A alone can finish the work in 60 days.
Given :
- A and B can complete work together = 30 days
- They worked for it for 20 days and then B left the work.
- The remaining work was done by A alone in 20 days more.
To find :
- No. of days A alone can finish the work =?
Step-by-step explanation :
A and B can work together = 30 days.
But A and B worked together for 20 days.
Total Work = L. C. M of 30, 20 = 60 unit
So, A and B work together,
60 units = 30 days
? = 20 days
So, 60 × 20/30 = 40 unit
Now,
We got that A and B take 20 days to complete 40 units.
A alone take 20 day's to complete 20 units,
= 1 unit /1 day
Therefore, 60 unit = 1 × 60 = 60 days.
Hence,
No. of days A alone can finish the work = 60 day's.
Option d). 60 day's is the correct option.