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 18 of 36.
Tania said:
1 decade ago
@kamalakannan
Because A alone does the work in FIRST day and in 3rd day he takes the help of B, C. So 1st A's 2daz work is calculated.
Because A alone does the work in FIRST day and in 3rd day he takes the help of B, C. So 1st A's 2daz work is calculated.
Harry matharoo said:
10 years ago
Now, 1/5 work is done in 3 days.
Whole work will be done in (3 x 5) = 15 days.
Where from 15 come from why we multiplied 3 with 5.
Whole work will be done in (3 x 5) = 15 days.
Where from 15 come from why we multiplied 3 with 5.
Sreelekshmi said:
9 years ago
3 day's work is 1/5.
So, 1 day's work is = 1/15.
Total no of day's to complete the work is (reciprocal of 1day's work) = 15 day's.
So, 1 day's work is = 1/15.
Total no of day's to complete the work is (reciprocal of 1day's work) = 15 day's.
Farha said:
1 decade ago
The question is not about to ask the work of 3 days. Then why we are finding 3 days's work.
Can anybody explain, I am so confused.
Can anybody explain, I am so confused.
G.prathyusha said:
6 years ago
To complete 1/5th of work - 3 days.
Hence to complete 5/5th of work - x days.
By cross multiply, you will get x value as 15 days.
Hence to complete 5/5th of work - x days.
By cross multiply, you will get x value as 15 days.
Ompal. said:
9 years ago
A, B, and C person can a do work 20, 40 and 60 days respectivily. When they works alternative. They compeleted work how many days.
Shridhar said:
9 years ago
A as done the work for 2 days, he is asserted to B and C in 3rd, he as not done the work at 3rd day. Then why 1/20 + 1/30 + 1/60?
Krishna said:
3 months ago
Here, A alone complete the whole work then answer is 20. Because total work is 60 and A's efficiency is 3.
Then 60/3 = 20 days.
Then 60/3 = 20 days.
(5)
Liza said:
1 decade ago
In 1/20+1/30+1/60 we take LCM of 20, 30, 60 i.e. 60 then,
60/20 = 3.
60/30 = 2.
60/60 = 1 then,
3+2+1 = 6.
So 6/60. Got it.
60/20 = 3.
60/30 = 2.
60/60 = 1 then,
3+2+1 = 6.
So 6/60. Got it.
Divyanshu Dwivedi said:
1 decade ago
It is much easier by this method :
1/20 + 1/(30*3) + 1/(60*3) = 1/x.
1/20 + 1/90 + 1/180 = 1/x.
12/180 = 1/x.
x = 15 Ans.
1/20 + 1/(30*3) + 1/(60*3) = 1/x.
1/20 + 1/90 + 1/180 = 1/x.
12/180 = 1/x.
x = 15 Ans.
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