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 22 of 35.

Rushikesh said:   6 years ago
@Pooja

(1/15)+(1/20).
[(20+15)/(15*20)],
= 35/300,
= 7/60.

Dipen said:   1 decade ago
How come Remaining work 1-7/15 (note:- why come 1 value )

Birander yadav said:   10 years ago
1/15+1/20 = 7/60*2 = 7/15.

Total work day = 1-7/15 = 8/15.

Portia said:   2 years ago
How did 1/15 +1/20 turn into 7/60? Someone, please explain.
(43)

Raju said:   9 years ago
In how many days A & B together complete the same job?

RichardAnthony said:   2 years ago
Just take LCM of 15 and 20 you will get total work of 60.
(17)

Sagar said:   1 decade ago
@deepa
lcm of 15 and 20 is 60 so we get 7/60
understood

Prem said:   1 decade ago
7/60 = 20+15/300. But I am not understanding last step.

Jenifer said:   8 years ago
@Shubam Mishra.

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

Hari said:   12 months ago
@Vishnu.

Can you explain the process in detail please?
(14)


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