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 29 of 36.
Raju said:
1 decade ago
Why we are takng 3*5 in last step please expain.
Preethi said:
1 decade ago
Why we are takng 3*5 in last step please expain.
Yogendra said:
1 decade ago
Thanks nikithas & bhaskar for your nice explanation.
Sandya said:
1 decade ago
@ nikita prasad
Its really good explanation. I had lot more confusion at this step. Now I'm clear. ThanQ.
Its really good explanation. I had lot more confusion at this step. Now I'm clear. ThanQ.
Bralow said:
1 decade ago
Why we multiply 3*5 in last step?
Shro said:
1 decade ago
Sorry Guys. Can somebody please explain me more clearly.
My doubt is
" when we say A+B+C =1/10.
it means we have considered 1 day's work of A,B,C and the answer 1/10 is total of all 3 together working days"
" so when we say A's 2 day's work = 1/10
it means we are considering only A's 2day's work "
So,finally when we add for 3 days= (1/10) + (1/10)
here 1/10 is A's 2day's work, but when we take 2nd time 1/10 then does'n it mean that we are considering all 3 working together's total 1/10 ????
As the given question is In how many days can A do the work if he is assisted by B and C on every third day?
Hope u can udnerstand what I wrote above ...
My doubt is
" when we say A+B+C =1/10.
it means we have considered 1 day's work of A,B,C and the answer 1/10 is total of all 3 together working days"
" so when we say A's 2 day's work = 1/10
it means we are considering only A's 2day's work "
So,finally when we add for 3 days= (1/10) + (1/10)
here 1/10 is A's 2day's work, but when we take 2nd time 1/10 then does'n it mean that we are considering all 3 working together's total 1/10 ????
As the given question is In how many days can A do the work if he is assisted by B and C on every third day?
Hope u can udnerstand what I wrote above ...
Subasish said:
1 decade ago
A's 1 day work = 1/20
B's 1 day work = 1/30
C's 1 day work = 1/60
since on 3rd day A get assistance of B & C
so 3 days work = A's 3 days work + ( B's + C's )1 day work
= 2*(1/20)+ 1/30 + 1/60
= 12/60 = 1/5
1/5 parts is done by 3 days
1 or whole part is done by (5*3)= 15 days
B's 1 day work = 1/30
C's 1 day work = 1/60
since on 3rd day A get assistance of B & C
so 3 days work = A's 3 days work + ( B's + C's )1 day work
= 2*(1/20)+ 1/30 + 1/60
= 12/60 = 1/5
1/5 parts is done by 3 days
1 or whole part is done by (5*3)= 15 days
Sai said:
1 decade ago
I still can't get clarification.
In the question they asked that in every 3rd day of A's work.
But in explanation how can you say for only 3 days.
In the question they asked that in every 3rd day of A's work.
But in explanation how can you say for only 3 days.
Raman(UIET,KUK) said:
1 decade ago
Guys check dis out........
as we know A will be assist by B & C every third day, so first two day A will work again
A's 1st day of work = 1/20
A's 2nd day of work = 1/20
(A+B+C)'s 3rd day of work = 1/20+1/30+1/60=1/10
total work of 3 days = 1/20+1/20+1/10=1/5
hence,
3 days of work = 1/5
1 day of work will be=1/5*3
=1/15
so work will complete in 15 days
as we know A will be assist by B & C every third day, so first two day A will work again
A's 1st day of work = 1/20
A's 2nd day of work = 1/20
(A+B+C)'s 3rd day of work = 1/20+1/30+1/60=1/10
total work of 3 days = 1/20+1/20+1/10=1/5
hence,
3 days of work = 1/5
1 day of work will be=1/5*3
=1/15
so work will complete in 15 days
(1)
Emmanuel said:
1 decade ago
Can someone help me out? why are they multiplying 3 and 5 but not any number for example 3 and 6 making 18 ?
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