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 9 of 36.
Sindhu said:
1 decade ago
@Baskar
Can you please explain me why do you cross multiply at the end for the answer?
Can you please explain me why do you cross multiply at the end for the answer?
Sathish said:
1 decade ago
Hi friends,
we know that whole work completed means we will denote it as 1(full)....
2=1(in 2days full work get completed)
5=1(in 5days full work get completed)
just simple 5=1/2 =>5*2=1(just cross multiple the 2)
we know that whole work completed means we will denote it as 1(full)....
2=1(in 2days full work get completed)
5=1(in 5days full work get completed)
just simple 5=1/2 =>5*2=1(just cross multiple the 2)
Preethi said:
1 decade ago
1/5 of work being done in 3 days. But how do we arrive at the total no. Of days worked by A? what is the logic behind?
Neetu singh said:
1 decade ago
@benny-reli nice explanation.
Harry said:
1 decade ago
1.)days worked by A is 2; 1 day helped by B and C and not A,
2.)given is A's 3 day work
3.)total 1 day work of A,B,C is find
4.)A's 2 day work is found
Result calculation:
A's 3day work=>(1/10)+(1/10)=>A 2day work+A,B,C's 1days)
=>1/5(of whole work) [5 is n]
A's whole work=3*5=15days
2.)given is A's 3 day work
3.)total 1 day work of A,B,C is find
4.)A's 2 day work is found
Result calculation:
A's 3day work=>(1/10)+(1/10)=>A 2day work+A,B,C's 1days)
=>1/5(of whole work) [5 is n]
A's whole work=3*5=15days
Anil said:
1 decade ago
Thanks benny.
Poornima said:
1 decade ago
How can you taking that 3 days? and 1/10+1/10 what is it ?
Imraz said:
1 decade ago
Here 15 days is required for the completion of the work by A, B, C. But in question it is asked 'in how many days can A do the work' - which means the number of days A worked. So to get this we need to divide the 15 by 3 and get '5' as answer.
Can anyone please make me clear if my interpretation is incorrect ?
Can anyone please make me clear if my interpretation is incorrect ?
Ganbrave said:
1 decade ago
@Poornima
A works for 2 days and B,C joins him on 3rd day.
so total combination of them is now 3days
Based on these 3days we can furthur calculate..ok??
A's 2 days work=1/10 and on 3rd day A,B,C together work=1/10
So sum of them gives u total 3days of work done by all of them.
A works for 2 days and B,C joins him on 3rd day.
so total combination of them is now 3days
Based on these 3days we can furthur calculate..ok??
A's 2 days work=1/10 and on 3rd day A,B,C together work=1/10
So sum of them gives u total 3days of work done by all of them.
Rohit said:
1 decade ago
1st day A's + 2nd day A's work = (1/20 + 1/20) = 2/20 = 1/10--(1)
3rd day work is added by B's and C's work so, work done by A+B+C=
(1/20+1/30+1/60) = 1/10--(2)
from (1) and (2)= 1/10+1/10 =1/10
3rd day work is added by B's and C's work so, work done by A+B+C=
(1/20+1/30+1/60) = 1/10--(2)
from (1) and (2)= 1/10+1/10 =1/10
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