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.
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)
B SUNDARA said:
8 years ago
Since B and C assisting A on every 3rd day, B & C takes 30x3=90 days and 60x3=180 days respectively to do the work.
Therefore
1/20+1/90+1/180 = 12/180 = 1/15 or 15 days.
Therefore
1/20+1/90+1/180 = 12/180 = 1/15 or 15 days.
(1)
Haphyz said:
1 decade ago
I think @Manoj made it simpler and direct. Get the portion of the job that would be completed in 3 days and then keep adding that portion in 3 days interval until you get 1.
A govardhan reddy said:
1 decade ago
A can do 20 days so = 1/20.
A can do with B and C every third day = 20/3 = 18+2 (alone).
A+B+C = (3/18+1/30+1/60) = 1/5.
So the A work done in three days = 5*3 = 15 days.
A can do with B and C every third day = 20/3 = 18+2 (alone).
A+B+C = (3/18+1/30+1/60) = 1/5.
So the A work done in three days = 5*3 = 15 days.
Kranthi said:
1 decade ago
A's 1 day work = 1/20
B every 3 days = 3/30
C also every 3 days = 3/60
Total work = 1/20+3/30+3/60
= 3+6+3/60 = 12/60 =1/5
3*5 days=full work completed
15
Is it correct way
B every 3 days = 3/30
C also every 3 days = 3/60
Total work = 1/20+3/30+3/60
= 3+6+3/60 = 12/60 =1/5
3*5 days=full work completed
15
Is it correct way
Durga said:
1 decade ago
LCM of 20,30,60 is 600
A's work is 600/20
if b and c on third day then 2 days(first and second) for A and 1 day for B and c(third day)
so A's work is 600/(20*2)=600/40=15
A's work is 600/20
if b and c on third day then 2 days(first and second) for A and 1 day for B and c(third day)
so A's work is 600/(20*2)=600/40=15
Poojitha said:
4 years ago
@Dhanam.
Because on third day they are doing combined work it means that for 1st 2 days they have worked alone here in question. About A has asked so he is doing only A.
Because on third day they are doing combined work it means that for 1st 2 days they have worked alone here in question. About A has asked so he is doing only A.
(3)
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.
Nitinkumar said:
1 decade ago
A+B+C=(1/20)+(1/30)+(1/60)=1/10
ON 3 RD DAY HE IS TAKING WORK FROM BOTH B&C HIS 2DAYS WORK +A+B+C WORK= 1/10+1/10 = 2/10 =1/5
MULTIPLY WIT 1/3 U LL GET 1/15
15 DAYS
ON 3 RD DAY HE IS TAKING WORK FROM BOTH B&C HIS 2DAYS WORK +A+B+C WORK= 1/10+1/10 = 2/10 =1/5
MULTIPLY WIT 1/3 U LL GET 1/15
15 DAYS
Harsha said:
9 years ago
According to the question the A has been assisted by B and C after the third day.
It means the A has to work for three days and the third day is followed by B and C.
It means the A has to work for three days and the third day is followed by B and C.
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