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 12 of 36.
Neha sharma said:
1 decade ago
I am Neha sharma I want to know,
How comes 6/60 = 1/10.
And 1/10 + 1/10 = 1/5.
If in 3 days work = 1/5 then how is that in 1 day =1/15.
Is it should be in 1 day 1/5 and by adding in 3 days =1/15.
Please tell me I gonne be confused.
How comes 6/60 = 1/10.
And 1/10 + 1/10 = 1/5.
If in 3 days work = 1/5 then how is that in 1 day =1/15.
Is it should be in 1 day 1/5 and by adding in 3 days =1/15.
Please tell me I gonne be confused.
Shreekanth said:
1 decade ago
@Vishnu...
As per the statement A will do the work three days continuosly but only on third day B & C will assist, so
A's thrid day work must also include with both B & C
that's why...
(A + B + C)'s 1 day's work is taken
As per the statement A will do the work three days continuosly but only on third day B & C will assist, so
A's thrid day work must also include with both B & C
that's why...
(A + B + C)'s 1 day's work is taken
Suram Ramana Reddy said:
4 weeks ago
A = 20/60 -> 3 units
B = 30/60 -> 2 units
C = 60/60 -> 1 unit
= 6 units.
L.C.M=60
B and C help on every third day, which means A can do the work alone for 2 days.
2 days A work = 3x3 = 9 units + 3rd day(A+B+C) 6 = 15.
B = 30/60 -> 2 units
C = 60/60 -> 1 unit
= 6 units.
L.C.M=60
B and C help on every third day, which means A can do the work alone for 2 days.
2 days A work = 3x3 = 9 units + 3rd day(A+B+C) 6 = 15.
(13)
Hrmridha said:
1 decade ago
A work in 3 days 3/20 part of the work.
Third day B and C work (1/30 + 1/60) = 1/20 part.
So, after 3 days work done by A, B and C = (3/20 + 1/20) = 1/5 part.
Now, 1/5 part done in 3 days.
1 part done in 5/1*3= 15 days (Ans).
Third day B and C work (1/30 + 1/60) = 1/20 part.
So, after 3 days work done by A, B and C = (3/20 + 1/20) = 1/5 part.
Now, 1/5 part done in 3 days.
1 part done in 5/1*3= 15 days (Ans).
Sindhu said:
1 decade ago
@Ashwini.
As they mentioned in the question A is assisted B and C on every third day means on every third day A B C do the work together. That means you have to add A B C 's one day work.
i.e 1/20+1/30+1/60 = 6/60 = 1/10.
As they mentioned in the question A is assisted B and C on every third day means on every third day A B C do the work together. That means you have to add A B C 's one day work.
i.e 1/20+1/30+1/60 = 6/60 = 1/10.
Praveen said:
9 years ago
(A + B + C) = 1/20 + 1/30 + 1/60.
Given 180/1800.
For 20, 30 & 60 the common multiple is 1800 (LCM).
Then you'll get the sum of 180/1800.
This is how I got 1/10 for the work done by A, B & C in 1 day.
Given 180/1800.
For 20, 30 & 60 the common multiple is 1800 (LCM).
Then you'll get the sum of 180/1800.
This is how I got 1/10 for the work done by A, B & C in 1 day.
Hitesh said:
1 decade ago
work done by A per day=1/20;
work done by B per day=1/30;
work done by C per day=1/60;
Let the work is completed in 3x days
So,
1/20*3x+1/30*x+1/60*x=1
=> x=5
=> No. of days required to complete the work=3*5=15days
work done by B per day=1/30;
work done by C per day=1/60;
Let the work is completed in 3x days
So,
1/20*3x+1/30*x+1/60*x=1
=> x=5
=> No. of days required to complete the work=3*5=15days
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.
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)
Akshara said:
6 years ago
Efficiency total work-60.
A - 20 days----> 3
B - 30 days----> 2
c - 60 days-----> 1
A+B+C work=6---->3 days work=12.
The total work to done is 60 hence 12 * 5=60.
Hence days are 5 * 3=15 is the right answer.
A - 20 days----> 3
B - 30 days----> 2
c - 60 days-----> 1
A+B+C work=6---->3 days work=12.
The total work to done is 60 hence 12 * 5=60.
Hence days are 5 * 3=15 is the right answer.
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