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 :
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:
347 comments Page 22 of 35.
Crompton said:
1 decade ago
Because we know that total work = 1 so we subtract with one.
Miru said:
8 years ago
1-{4(1/15+1/20)}
=1-{4*7/60}
=1-1/15
8/15 is the answer (d).
=1-{4*7/60}
=1-1/15
8/15 is the answer (d).
Rushikesh said:
6 years ago
@Pooja
(1/15)+(1/20).
[(20+15)/(15*20)],
= 35/300,
= 7/60.
(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:
1 decade ago
1/15+1/20 = 7/60*2 = 7/15.
Total work day = 1-7/15 = 8/15.
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:
3 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
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.
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