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 15 of 36.
Suresh Kumar said:
1 decade ago
@Divya.
First Two days work done by A = (1/20)+(1/20)=> 2/20=> 1/10.
Third day work done by A,B,C = (1/20)+(1/30)+(1/60)=> 6/60 => 1/10.
Total work Done in 3 days= (1/10)+(1/10)=2/10 =>1/5.
First Two days work done by A = (1/20)+(1/20)=> 2/20=> 1/10.
Third day work done by A,B,C = (1/20)+(1/30)+(1/60)=> 6/60 => 1/10.
Total work Done in 3 days= (1/10)+(1/10)=2/10 =>1/5.
Anurag said:
1 decade ago
Let N be the total no.of days A has to work. So, a/q B and C works only for N/3 days. Total work = 1.
Therefore,
N*(1/20)+ (N/3)*((1/30)+(1/60)) = 1.
Solving this , you will get N = 15.
Therefore,
N*(1/20)+ (N/3)*((1/30)+(1/60)) = 1.
Solving this , you will get N = 15.
Seema duhan said:
1 decade ago
First Two days work done by A = (1/20)+(1/20)=> 2/20=> 1/10.
Third day work done by A, B, C = (1/20)+(1/30)+(1/60)=> 6/60 => 1/10.
3 days work done: 1/5.
Then 1 day work done: (1/5)*(1/3) = 1/15.
So the answer is 115 days.
Third day work done by A, B, C = (1/20)+(1/30)+(1/60)=> 6/60 => 1/10.
3 days work done: 1/5.
Then 1 day work done: (1/5)*(1/3) = 1/15.
So the answer is 115 days.
Sundas said:
1 decade ago
I didn't get step 1 how a 2 days work? I mean why we multiply with 2?
Ganesh said:
1 decade ago
Guys, as per my understanding,
1st day A complete 1/20th of work.
2nd day A completes 2/20th of work.
3rd day A along with B and C completes (3/20+1/30+1/60) i.e., 1/5th of the work.
Could some one explain how to calculate?
4th day of A's work ?
5th day of A's work?
6th day of A along with B and C ?
1st day A complete 1/20th of work.
2nd day A completes 2/20th of work.
3rd day A along with B and C completes (3/20+1/30+1/60) i.e., 1/5th of the work.
Could some one explain how to calculate?
4th day of A's work ?
5th day of A's work?
6th day of A along with B and C ?
Arijit Roy said:
1 decade ago
It would be better if it is done in this way.
B, C assist A on the 3rd day so directly we get,
3/20(3 day's of A) + 1/30(assistance of B) + 1/60(assistance of C) = 1/5.
So 1/5 done in 3 days whole is done in 15 days.
B, C assist A on the 3rd day so directly we get,
3/20(3 day's of A) + 1/30(assistance of B) + 1/60(assistance of C) = 1/5.
So 1/5 done in 3 days whole is done in 15 days.
Bond said:
1 decade ago
1/5 of work --->3 days.
1 complete work ---> ?
= (1*3)/(1/5).
= 15 days.
1 complete work ---> ?
= (1*3)/(1/5).
= 15 days.
Siddalingaswamy c said:
1 decade ago
1/20+1/30+1/60=6/60. Can any one say the 6 came in 6/60?
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.
Nitish Mehta said:
1 decade ago
@Liza. What will you do after calculate 6/60?
Complete your answer.
Complete your answer.
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