Aptitude - Time and Work - Discussion

Discussion Forum : Time and Work - General Questions (Q.No. 1)
1.
A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the fraction of the work that is left is :

1
4

1
10

7
15

8
15

Answer: Option
Explanation:

A's 1 day's work = 1 ;
15

B's 1 day's work = 1 ;
20

(A + B)'s 1 day's work = ( 1 + 1 ) = 7 .
15 20 60

(A + B)'s 4 day's work = ( 7 x 4 ) = 7 .
60 15

Therefore, Remaining work = ( 1 - 7 ) = 8 .
15 15

Discussion:
344 comments Page 3 of 35.

Rajesh Chowdary said:   1 decade ago
Explanations are good plz share any simple methods other than these

Trupti said:   1 decade ago
1-7/15 should be 6/15 please explaine how 8/15......

Parthiban said:   1 decade ago
@Trupti

1-7/15 = (15-7)/15 = 8/15

I hope this will help you !

Trupti said:   1 decade ago
Thanks Parthiban. I understood well.

Latha said:   1 decade ago
Why the rest part is only 1-7/15 ?

Anshuman said:   1 decade ago
Oh! Thanks I understood well.

Vikas said:   1 decade ago
Thanks for your explanation. But it take much time. Can you tell me tricks.

Suba said:   1 decade ago
Why we subtract with one? can you please explain.

Crompton said:   1 decade ago
Because we know that total work = 1 so we subtract with one.

Depl said:   1 decade ago
Oh! Thanks I understood well.


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