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:
351 comments Page 30 of 36.

Sagar said:   9 years ago
How to 300 come? Explain.

NISHA said:   9 years ago
Why sub this (1-7/15) can you explain?

Shubham mishra said:   9 years ago
@Ankit kain.

In the last step why you take 28/60 instead of 60/28?

Jenifer said:   9 years ago
@Shubam Mishra.

Because 60 is just the value of L.C.M.

Shiva said:   9 years ago
Why sub (1-7/15)? please explain.

Asi ganesh said:   9 years ago
Why sub (1-7/15)?

I can explain

7/15 is A, B are together work in 4 days
Then question is remaining work is nothing but left this work is total work is 1 and remaining work is is nothing but all of you know
(1-7/15)=8/15.

Karthik said:   8 years ago
How comes 300 please explain?

Prabhu said:   8 years ago
Can anyone solve this?

Problem: 'A' can do a piece of in 6days, 'B' in 9days and 'C' in 12 days. In how many days will all of the together finish the work?

Dhananjay Moundekar said:   8 years ago
@Prabhu.

6d/w <= A---->6d
4d/w <= B---->9d
3d/w <= C----->12d

Total Work is LCM of A,B,C =36W

They All do toghether means,
A+B+C=>6+4+3=13d/w
Therefore, A + B + C = 36w/13d/w=2*10/13.

Sneha said:   8 years ago
Therefore, A + B + C = 36w/13d/w=2*10/13. How is it? please explain.


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