Aptitude - Time and Work - Discussion

Discussion Forum : Time and Work - General Questions (Q.No. 28)
28.
X can do a piece of work in 40 days. He works at it for 8 days and then Y finished it in 16 days. How long will they together take to complete the work?

13 1 days
3

15 days
20 days
26 days
Answer: Option
Explanation:

Work done by X in 8 days = ( 1 x 8 ) = 1 .
40 5

Remaining work = ( 1 - 1 ) = 4 .
5 5

Now, 4 work is done by Y in 16 days.
5

Whole work will be done by Y in ( 16 x 5 ) = 20 days.
4

Therefore X's 1 day's work = 1 , Y's 1 day's work = 1 .
40 20

(X + Y)'s 1 day's work = ( 1 + 1 ) = 3 .
40 20 40

Hence, X and Y will together complete the work in ( 40 ) = 13 1 days.
3 3

Discussion:
33 comments Page 4 of 4.

Irshad said:   1 decade ago
Let x can do 1 work in a hour. Then he will do 8 work in 8 hour.

Remaining work = 40-8 = 32.

32/y=16;
y=2.

Means y do 1 work in 2hours.
x+y=3.

Together they will do in 40/3 day.

NARAYAN SAHOO said:   1 decade ago
x=40-8=32 ratio 2 capacity 1
y=16 ratio 1 capacity 2

Together done ration 3
Work is 40
Then 40/3
13.1/3

Bala said:   1 decade ago
Why you convert 4/5 into 5/4?


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