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 13 of 35.
Swetha said:
3 years ago
First of all, thank you to explain the method.
I have a doubt that how we know to take (i.e Total work = 60)?
Anyone, please help me to get it.
I have a doubt that how we know to take (i.e Total work = 60)?
Anyone, please help me to get it.
(6)
ANI KONAR said:
9 years ago
Short trick:
15, 20 LCM 60.
4, 3 efficiency.
4 + 3 = 7 in 1 day.
7 * 4 = 28 in 4 days.
Remaining = 60 - 28 = 32.
In fraction 32/60 = 8/15.
15, 20 LCM 60.
4, 3 efficiency.
4 + 3 = 7 in 1 day.
7 * 4 = 28 in 4 days.
Remaining = 60 - 28 = 32.
In fraction 32/60 = 8/15.
Tricky said:
1 decade ago
Efficiency Method:
Total 60 unit.
A = 60/15 = 4.
B = 60/20 = 3.
Total = 7/60.
In 4 days = 4*7/60 = 28/60 = 7/15.
Remain = 1-7/15 = 8/15.
Total 60 unit.
A = 60/15 = 4.
B = 60/20 = 3.
Total = 7/60.
In 4 days = 4*7/60 = 28/60 = 7/15.
Remain = 1-7/15 = 8/15.
Rahul said:
1 decade ago
Ok.
I guess the easier way to explain this is to subtract(20days-14days)= 5 days,
We have calculated for 4 days, therfore remaining is 1;)
I guess the easier way to explain this is to subtract(20days-14days)= 5 days,
We have calculated for 4 days, therfore remaining is 1;)
Prasad said:
1 decade ago
(1/15+1/20) = 7/60.
Explanation:
15 = 5*3.
20 = 5*4.
Here the common nums are 3,4,5.
3*4*5 = 60.
60/15 = 4.
60/20 = 3.
(3/60+4/60) = 7/60.
Explanation:
15 = 5*3.
20 = 5*4.
Here the common nums are 3,4,5.
3*4*5 = 60.
60/15 = 4.
60/20 = 3.
(3/60+4/60) = 7/60.
RPV said:
10 years ago
Why in this sum answer is not reciprocated in time and work problem the answer must be in reciprocal? Ex. 8/15 is written as 15/8 am correct.
RPV said:
10 years ago
Tulsi and Ram can do a job alone in 20 days and 30 days respectively. In how many days the job will be finished if they work together?
Jansi said:
1 decade ago
I understood upto 7/15. I can't understand how they are telling total work 1. From that they were minusing 7/15 can you explain me.
Aravind_appu said:
1 decade ago
A = 1/15.
B = 1/20.
Together TH = A+B.
TH = (1/15+1/20).
TH/4 = (1/15+1/20).
TH = 4((35/15*20)).
TH = 7/15.
= 1-7/15 = 8/15.
B = 1/20.
Together TH = A+B.
TH = (1/15+1/20).
TH/4 = (1/15+1/20).
TH = 4((35/15*20)).
TH = 7/15.
= 1-7/15 = 8/15.
ASHLYMOL SAJU said:
10 years ago
A B A+B.
15 20 4.
Work = Efficiency/Time.
Work = LCM of A B A+B.
W = 60.
A B A+B = 4 3 15.
Total = 7/15.
Remaining = 8/15.
15 20 4.
Work = Efficiency/Time.
Work = LCM of A B A+B.
W = 60.
A B A+B = 4 3 15.
Total = 7/15.
Remaining = 8/15.
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