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 10 of 35.

Sangeetha said:   1 decade ago
Yes swetha your are right. Its very simple and easy method. Thank you.

Hashir Quraishi said:   1 decade ago
Swetha you rocked.

Gowtham said:   1 decade ago
How came remaining days?

Kamal said:   1 decade ago
I didn't undestand last step.

Akanksha said:   1 decade ago
(1/50+1/20) = (20+15)/300 //This get by cross multiplication.

= 35/300

= 7/60.

How did 300 came?

Neha garg said:   1 decade ago
Let total work is 1
1/15+1/20=x/4
7/60*4=x
that means x=7/15
1-7/15=8/15

Fouzia said:   1 decade ago
Fouzia.

How that 7 came I can't got it?

SRI HARSHA.P said:   1 decade ago
The way said by swetha is very long process.
that wastes time in the exam hall.
thats not the good way to do the problem.
always prepare for ashort method.
Short method takes time for the first time by practice it gives u TIME MANAGEMENT. So better to practice SM.

Ramkumar said:   1 decade ago
Nice work swetha.

Swetha said:   1 decade ago
@Sri harsha.p

It is not very long process..it is short method only.i explained every steps.,so only it looks like long process.


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