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 28 of 35.

Santhosh said:   8 years ago
Can anyone explain this in LCM method?

Prashant Devada said:   8 years ago
@Akash.

You are great, LCM concept makes easy to understand.

Thanks.

Praveen behera said:   8 years ago
Why (1- 7/15) is applied as 8/15?

Can anybody explain it please?

Juhi saxena said:   8 years ago
If both 1 day work is 7 then 4 days work is 28 and remaining is 32 how can I change it into fraction? Please explain.

Dhanalakshmi said:   8 years ago
Thanks for your explanation @Swetha.

Shubham said:   8 years ago
Thanks for the explanation @Swetha.

SUNDARA said:   8 years ago
A & B together requires 1/15+1/20=7/60 or 60/7days =8 4/7 days to complete the work.

After 4 days work, pending work is 8 4/7 -4=4 4/7days work.

= 4 4/7 divide by 8 4/7=32/7 divide 60/7=32/60=8/15 work pending.

Pooja said:   8 years ago
How, (7/60 * 4) = 7/15?

Aadesh said:   8 years ago
28/60=14/30=7/15 @Pooja.

San said:   8 years ago
Here, 1/15+1/20= 20+15/300= 35/300 =7/60.


Post your comments here:

Your comments will be displayed after verification.