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 17 of 36.
Teja said:
10 years ago
This is question which is completely related to alternate days.
In alternate days question whenever work done is not given you have to take it as '1'.
Here we got that 1/5 of the work is done in 3 days which means 1/5 work=3 days.
1=how many days?
Cross multiply, you get days=15.
This concept works for all of the alternate days question. When ever work is not given take it as '1'.
In alternate days question whenever work done is not given you have to take it as '1'.
Here we got that 1/5 of the work is done in 3 days which means 1/5 work=3 days.
1=how many days?
Cross multiply, you get days=15.
This concept works for all of the alternate days question. When ever work is not given take it as '1'.
Vani said:
10 years ago
In last step why did they multiplied with 3?
Vicky said:
10 years ago
Please anyone give clear explanation I confused.
Harry matharoo said:
10 years ago
Now, 1/5 work is done in 3 days.
Whole work will be done in (3 x 5) = 15 days.
Where from 15 come from why we multiplied 3 with 5.
Whole work will be done in (3 x 5) = 15 days.
Where from 15 come from why we multiplied 3 with 5.
Venkat said:
10 years ago
Please tell me how 3 is coming in the last step?
Venkat said:
10 years ago
3 = 1/5.
So, our complete work done at 1.
So, 3*5 = 1/5*5.
15 = 1.
So, our complete work done at 1.
So, 3*5 = 1/5*5.
15 = 1.
Junaid said:
10 years ago
A do 1/20 = 0.05 work daily and in 4 days he do 0.05+0.05+0.05+0.05 = 0.2 work.
But with the help of B and C the 4 days work is done in 3 days in this way.
= 0.05+0.05+(0.05+1/30+1/60) = 0.2.
Then every 4 days work is done in 3 days up-to 20 days.
So 3+3+3+3+3 = 15.
But with the help of B and C the 4 days work is done in 3 days in this way.
= 0.05+0.05+(0.05+1/30+1/60) = 0.2.
Then every 4 days work is done in 3 days up-to 20 days.
So 3+3+3+3+3 = 15.
Onkar said:
10 years ago
A can complete a work in 20 days, B can complete the same work in 30 days and with the help of C together if they complete the work in 60 days, so assume total work to be done is 60. (LCM of 20, 30, 60).
Persons A B C per 3 day.
Days- 20 30 60 12 = 6+6.
Work/day- 3 2 1 5.
----------------------------------------------------------------.
Work - 60 60 60 60.
Per 3 day ----> 12.
How many ----> 60 = (60*3)/12 = 15 days required.
Days required.
Persons A B C per 3 day.
Days- 20 30 60 12 = 6+6.
Work/day- 3 2 1 5.
----------------------------------------------------------------.
Work - 60 60 60 60.
Per 3 day ----> 12.
How many ----> 60 = (60*3)/12 = 15 days required.
Days required.
Nitin said:
10 years ago
A = 20 = 1 day work of A = 3 LCM = 60.
B = 30 = 1 day work of B = 2.
C = 60 = 1 day work of C = 1.
Day 1 2 3 1 2 3.
Work 3 3 (A+B+C = 3+2+1).
Work of 3 days = 2(A) + (A+B+C).
2*3+(3+2+1) = 12.
3 days = 12 unit work (which number we multiply both side that do not greater than the total unit work).
3*5 days = 12*5 unit work.
15 days = 60 unit.
B = 30 = 1 day work of B = 2.
C = 60 = 1 day work of C = 1.
Day 1 2 3 1 2 3.
Work 3 3 (A+B+C = 3+2+1).
Work of 3 days = 2(A) + (A+B+C).
2*3+(3+2+1) = 12.
3 days = 12 unit work (which number we multiply both side that do not greater than the total unit work).
3*5 days = 12*5 unit work.
15 days = 60 unit.
Praveen said:
10 years ago
1/5x100-20 percent work done in 3 days therefore for 100 cross multiply 15 days.
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