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:
345 comments Page 31 of 35.
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.
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.
Fouzia said:
1 decade ago
Fouzia.
How that 7 came I can't got it?
How that 7 came I can't got it?
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
1/15+1/20=x/4
7/60*4=x
that means x=7/15
1-7/15=8/15
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?
= 35/300
= 7/60.
How did 300 came?
Kamal said:
1 decade ago
I didn't undestand last step.
Gowtham said:
1 decade ago
How came remaining days?
Hashir Quraishi said:
1 decade ago
Swetha you rocked.
Sangeetha said:
1 decade ago
Yes swetha your are right. Its very simple and easy method. Thank you.
Pradeepshne said:
1 decade ago
Wow really superb.
Swetha said:
1 decade ago
We can solve this problem by another way also..let us see..
A can do a work in 15 days
B can do a work in 20 days
Take LCM for 15 & 20 i.e Total work = 60
Then,
A's capacity = 60/15 = 4
B's capacity = 60/20 = 3
They work together for 4 days,
Then, A's capacity + B's capacity = 4 + 3 =7
AB's one day capacity = 7
since they work for 4 days, they have done 4x7 =28 work
Work left = Total work - work done by AB
= 60 - 28 = 32
Remaining work / total work = 32 / 60 = 8 / 15
This method will take less time to compute guys...please try it.
A can do a work in 15 days
B can do a work in 20 days
Take LCM for 15 & 20 i.e Total work = 60
Then,
A's capacity = 60/15 = 4
B's capacity = 60/20 = 3
They work together for 4 days,
Then, A's capacity + B's capacity = 4 + 3 =7
AB's one day capacity = 7
since they work for 4 days, they have done 4x7 =28 work
Work left = Total work - work done by AB
= 60 - 28 = 32
Remaining work / total work = 32 / 60 = 8 / 15
This method will take less time to compute guys...please try it.
(1)
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