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 32 of 35.
Jeevanantham M said:
2 years ago
@Ayansh.
For this;
(A+B) 's work rate = 1/15 + 1/20 = (4/60 + 3/60) = 7/60.
For this;
(A+B) 's work rate = 1/15 + 1/20 = (4/60 + 3/60) = 7/60.
(21)
Dinesh kumar said:
2 years ago
A = 1/15
B = 1/20
(A+B) = 1/15+1/20 = 7/15
The remaining work = 1-7/15 = 8/15.
B = 1/20
(A+B) = 1/15+1/20 = 7/15
The remaining work = 1-7/15 = 8/15.
(26)
Zak said:
2 years ago
How come 7/60? Please explain.
(29)
Mish said:
2 years ago
@All.
Why (A+B)'s 4 days of work is calculated?
Why it's not 3,5,6,7 or any other day?
What is the logic behind it?
Why (A+B)'s 4 days of work is calculated?
Why it's not 3,5,6,7 or any other day?
What is the logic behind it?
(10)
Giri said:
2 years ago
Just take LCM on 15 and 20 of 60.
Total work 60.
Capacity A 4 and capacity B 3 total 7.
They both worked together for 4 days and completed work 28.
Remaining work 32/60,
So, the Answer 8/15.
Total work 60.
Capacity A 4 and capacity B 3 total 7.
They both worked together for 4 days and completed work 28.
Remaining work 32/60,
So, the Answer 8/15.
(60)
Durga prasad said:
2 years ago
Lcm of 15 and 30 = 60 units.
A's per day work = 60/15 = 4units.
B's per day work = 60/20 = 3units.
A+B's per day work = 4 + 3 = 7units.
A and B together do the work in 4 days.
= 4 * 7 = 28units.
Remaining work = 32/60 = 8/15.
A's per day work = 60/15 = 4units.
B's per day work = 60/20 = 3units.
A+B's per day work = 4 + 3 = 7units.
A and B together do the work in 4 days.
= 4 * 7 = 28units.
Remaining work = 32/60 = 8/15.
(196)
NADIPUDI SIRISHA said:
2 years ago
Thank you for explaining the answer @Giri.
(26)
Portia said:
2 years ago
How did 1/15 +1/20 turn into 7/60? Someone, please explain.
(43)
Sahil said:
2 years ago
4( 1/15 + 1/20 ) = work done by both of them together
Work Done + Work left =1 =>because the work is 100% completed
4( 1/15 + 1/20 ) + work left = 1;
work left = 1 - (28/ 60);
Then, work left = 8/15;
Work Done + Work left =1 =>because the work is 100% completed
4( 1/15 + 1/20 ) + work left = 1;
work left = 1 - (28/ 60);
Then, work left = 8/15;
(66)
Lakshmanan S said:
2 years ago
How come remaining work 1- 7/15? Please explain me.
(71)
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