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:
344 comments Page 26 of 35.
Abhinesh said:
7 years ago
Let,
Do in this way;
Use formula= xy/x+y.
X is 15 and Y 30 if you cross multiply you get an answer.
Do in this way;
Use formula= xy/x+y.
X is 15 and Y 30 if you cross multiply you get an answer.
TRUPTIMAYEE BAHINIPATI said:
7 years ago
Why we subtract 7/15 by 1?
Solution:
Here we consider that the total work is 1.
A&B do a certain work that we don't know so at first we need find the unit of work in 1day
then A+B's working unit per 4 days.
After that we got A&B's total unit of work done ;which is substrated by 1 to got the remaining work.
Solution:
Here we consider that the total work is 1.
A&B do a certain work that we don't know so at first we need find the unit of work in 1day
then A+B's working unit per 4 days.
After that we got A&B's total unit of work done ;which is substrated by 1 to got the remaining work.
Fazeena said:
7 years ago
I can't understand 1-7/15.
So, please explain me again or another way.
So, please explain me again or another way.
Jagannath naik said:
7 years ago
How to find 1/15?
Nikhil said:
7 years ago
@Fazeena.
The work completed in 4 days is 7/15. Therefore remaining work is 1-(7/15). So, total work is 1.
The work completed in 4 days is 7/15. Therefore remaining work is 1-(7/15). So, total work is 1.
Krish Magesh said:
7 years ago
A's 1 day's work = 1/15.
B's 1 day's work = 1/20.
(A+B)'s 1 day's work= (1/15+1/20),
= 20+15/300(cross multiplication),
= 35/300,
= 7/60.
(A+B)'s 4 day's work= 7/60 * 4,
= 7/15(60/4 is division it is 15).
Therefore remaining work=1 - 7/15,
= 15-7/15,
= 8/15.
B's 1 day's work = 1/20.
(A+B)'s 1 day's work= (1/15+1/20),
= 20+15/300(cross multiplication),
= 35/300,
= 7/60.
(A+B)'s 4 day's work= 7/60 * 4,
= 7/15(60/4 is division it is 15).
Therefore remaining work=1 - 7/15,
= 15-7/15,
= 8/15.
Leela krishna said:
7 years ago
Can you explain the step 7÷60?
Laxman said:
7 years ago
A's 1 day's work = 1/15.
B's 1 day's work = 1/20.
(A+B)'s 1 day's work= (1/15+1/20),
L.C.M of 15,20 is 60 then,
15*4=60, 20*3=60,
4 + 3/60=7/60.
B's 1 day's work = 1/20.
(A+B)'s 1 day's work= (1/15+1/20),
L.C.M of 15,20 is 60 then,
15*4=60, 20*3=60,
4 + 3/60=7/60.
Sasikumar said:
7 years ago
The total work of A& B is = 60.
we can get 60 by taking LCM of it.
A's one day work = 4.
B's one day work = 3.
Both A & B 's one day work=7.
A's 4days work=4*4=16.
B's 4 days work=4*3=12.
So, A&B work=28.
The remaining work=60-28=32.
= 32/60,
= 8/15.
we can get 60 by taking LCM of it.
A's one day work = 4.
B's one day work = 3.
Both A & B 's one day work=7.
A's 4days work=4*4=16.
B's 4 days work=4*3=12.
So, A&B work=28.
The remaining work=60-28=32.
= 32/60,
= 8/15.
Vinay gudipati said:
7 years ago
Very simple,
15+20=35,
15*20=300,
35/300=7/60,
work is 1 so=1-7/15.
=15-7/15,
Ans is = 8/15.
15+20=35,
15*20=300,
35/300=7/60,
work is 1 so=1-7/15.
=15-7/15,
Ans is = 8/15.
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