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.
Sreelekshmi said:
9 years ago
3 day's work is 1/5.
So, 1 day's work is = 1/15.
Total no of day's to complete the work is (reciprocal of 1day's work) = 15 day's.
So, 1 day's work is = 1/15.
Total no of day's to complete the work is (reciprocal of 1day's work) = 15 day's.
Anu said:
9 years ago
A = 20, B = 30 &C = 60.
Total work (LCM of 20, 30, 60) = 60.
A's 1day work= 60/20 = 3units.
B's 1day work= 60/30 = 2.
C's 1day work= 60/60 = 1.
1st day A will do the work =3 unit.
2nd day again A will do the work = 3.
In 3rd-day, A + B + C will do the work = 3 + 2 + 1 = 6.
After 3 days total work = 12 (3 + 3 + 6).
After 6 days total work = 24.
Similarly;
After 12 days total work = 48.
15 days total work = 60.
So total no days to complete the work (60) is 15 days.
Total work (LCM of 20, 30, 60) = 60.
A's 1day work= 60/20 = 3units.
B's 1day work= 60/30 = 2.
C's 1day work= 60/60 = 1.
1st day A will do the work =3 unit.
2nd day again A will do the work = 3.
In 3rd-day, A + B + C will do the work = 3 + 2 + 1 = 6.
After 3 days total work = 12 (3 + 3 + 6).
After 6 days total work = 24.
Similarly;
After 12 days total work = 48.
15 days total work = 60.
So total no days to complete the work (60) is 15 days.
SRINIVAS said:
9 years ago
How A's 2 day's work = 1/10? Please explain the step.
Aaron said:
9 years ago
At the last step 1/5 * 3 we must do reciprocal right?
Or just multiple and get 15 for the sake of the answer in the options. Please tell me.
Or just multiple and get 15 for the sake of the answer in the options. Please tell me.
Ismail said:
9 years ago
Why didn't we take first B + C one day work is 1/30 + 1/60 = 1/20?
Please explain me.
Please explain me.
Bhavnesh said:
9 years ago
Hi friends.
I just want to know why we are taking 3 days work for 1/10 + 1/10.
I just want to know why we are taking 3 days work for 1/10 + 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.
Rayhan said:
9 years ago
Good explanation. I really understand this. Thankyou all.
Aariz said:
9 years ago
Hey, guys. I have some confusion in this question. Is there anyone from Delhi, please guide me to solve this question.
Preethu said:
9 years ago
Why do we multiply it by 5?
How we get the answer as 15? Please help me.
How we get the answer as 15? Please help me.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers