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 5 of 36.
Amit bhau said:
4 years ago
3 days ---> work 1/5
x days ---> to get total work =1
Cross multiplication, then we get x = 15.
x days ---> to get total work =1
Cross multiplication, then we get x = 15.
(1)
Kiran said:
4 years ago
Hi, can anyone tell me what's wrong here?
Given,
A=20days.
B=30days.
C=60days.
I took as 60units of work by taking LCM of A, B, C.
A's one day work=3 units/day.
B's one day work=2 units/day.
A's two days work = 6 units.
B's one day work= 2 units.
C's one day work= 1 unit.
A+B+C's 3 days work = 9 units.
So, I can take A+B+C's one day work = 3 units =>9/3=3 units/day.
So, to complete 60 units of work they will take 20days =>20*3=60 units.
So, I am saying that answer is "20 days".
Correct me if I'm wrong.
Given,
A=20days.
B=30days.
C=60days.
I took as 60units of work by taking LCM of A, B, C.
A's one day work=3 units/day.
B's one day work=2 units/day.
A's two days work = 6 units.
B's one day work= 2 units.
C's one day work= 1 unit.
A+B+C's 3 days work = 9 units.
So, I can take A+B+C's one day work = 3 units =>9/3=3 units/day.
So, to complete 60 units of work they will take 20days =>20*3=60 units.
So, I am saying that answer is "20 days".
Correct me if I'm wrong.
(1)
Sairam said:
4 years ago
@Kiran.
You didn't account for A's third day of work.
A does 6 units of work in two days and another 3 units on the third day. So in total, A has done 9 units of work in 3 days.
You didn't account for A's third day of work.
A does 6 units of work in two days and another 3 units on the third day. So in total, A has done 9 units of work in 3 days.
(1)
Madhu said:
3 days ago
Yes, I think 20 is the correct answer.
(1)
Chirag Lakhani said:
2 decades ago
How step 3 is make 1/10+1/10? please explain it.
Abhishek said:
1 decade ago
@chirag:
Step 3 gives work done in first 3 day i.e. work done in 1st day + work done in 2nd day +work done in 3rd day = 1/20 (by A alone) + 1/20 (by B alone) + 1/10 (done by A, B and C together)
Similarly they continue and as per the question on every 3rd day A is joined by B and C.
Step 3 gives work done in first 3 day i.e. work done in 1st day + work done in 2nd day +work done in 3rd day = 1/20 (by A alone) + 1/20 (by B alone) + 1/10 (done by A, B and C together)
Similarly they continue and as per the question on every 3rd day A is joined by B and C.
Nitesh Nandwana said:
1 decade ago
Hi chirag don't go on step, here our aim is to compute total work done in 3 days once, first 2 days A is working alone and last 3rd day we are adding work's of B and C.
Sushant said:
1 decade ago
(A + B + C)'s 1 day's work = 1 + 1 + 1 = 6 = 1 .
20 30 60 60 10
how did we get 60
20 30 60 60 10
how did we get 60
Bala said:
1 decade ago
I can't get this.
Dhanam said:
1 decade ago
Why are you taking 2 days for first step?
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