Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 3)
3.
A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?
Answer: Option
Explanation:
| A's 2 day's work = |  |
1 | x 2 |  |
= | 1 | . |
| 20 | 10 |
| (A + B + C)'s 1 day's work = | |
1 | + | 1 | + | 1 | |
= | 6 | = | 1 | . |
| 20 | 30 | 60 | 60 | 10 |
| Work done in 3 days = | |
1 | + | 1 | |
= | 1 | . |
| 10 | 10 | 5 |
| Now, | 1 | work is done in 3 days. |
| 5 |
Whole work will be done in (3 x 5) = 15 days.
Discussion:
357 comments Page 32 of 36.
Shambhawi said:
7 years ago
I have a very simple solution.
Here it is ->
Let the total number of days in which the work is finished is x.
A will work for x days, B and C will work for x/3 days.
Thus, (A's x days of work) + (B's x/3 days of work) + (C's x/3 days of work) = 1.
Thus -> x/20 + x/(3*30) + x/(3*60) = 1,
Thus-> x = 15.
Here it is ->
Let the total number of days in which the work is finished is x.
A will work for x days, B and C will work for x/3 days.
Thus, (A's x days of work) + (B's x/3 days of work) + (C's x/3 days of work) = 1.
Thus -> x/20 + x/(3*30) + x/(3*60) = 1,
Thus-> x = 15.
Mamun said:
7 years ago
Thanks all.
Pakiil said:
7 years ago
The work done in 3 days is 1/5.
So the work remaining is 4/5.
1/5=3 days,
2/5=3 days,
3/5=3 days,
4/5= 3 days,
5/5= 3 days,
The total days=15.
So the work remaining is 4/5.
1/5=3 days,
2/5=3 days,
3/5=3 days,
4/5= 3 days,
5/5= 3 days,
The total days=15.
Manish Raj said:
7 years ago
A's work = 20,
A+B+C = 10,
Together {A+(A+B+C)}/2 = (30+20)/2 = 15.
A+B+C = 10,
Together {A+(A+B+C)}/2 = (30+20)/2 = 15.
Lavanya said:
7 years ago
The total work done for three days means. There should be 1/10+1/10+1/10 should come right. Why they used it for 2 days only?
Md Toufique said:
7 years ago
Let us suppose total work to be done is 60 unit, then A, B and C's one day work is 3, 2, 1 respectively,
Then in every 3 days they will finish 12 unit of work (3, 3, 6),
Then, 12 + 12 + 12 + 12+ 12 =60 work done so total days = 3+3+3+3+3=15.
Then in every 3 days they will finish 12 unit of work (3, 3, 6),
Then, 12 + 12 + 12 + 12+ 12 =60 work done so total days = 3+3+3+3+3=15.
Rishi said:
7 years ago
How can you say the total work is 1?
Sha said:
7 years ago
How does the last step is (3*5=15)?
How come 3 here?
How come 3 here?
Dipankar said:
7 years ago
12-60.
1-5,
So 3=5*3=15.
1-5,
So 3=5*3=15.
Prem K said:
7 years ago
A's 1 day's work is 1/20.
A's 3 day's work is 3/20.
(B+C)'s 1 day's work is 1/30+1/60 = 1/20.
B and C will work on every third day means A will work three days and B and C will work for 1 day.
(A+B+C)'s 3 day's work = A's 3 day's work + (B+C)'s 1 day's work,
= 3/20 + 1/20,
= 1/5.
3 day's work is 1/5 then, whole work will be done in (3*5) = 15 days.
A's 3 day's work is 3/20.
(B+C)'s 1 day's work is 1/30+1/60 = 1/20.
B and C will work on every third day means A will work three days and B and C will work for 1 day.
(A+B+C)'s 3 day's work = A's 3 day's work + (B+C)'s 1 day's work,
= 3/20 + 1/20,
= 1/5.
3 day's work is 1/5 then, whole work will be done in (3*5) = 15 days.
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