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 26 of 36.
SRINIVAS said:
9 years ago
How A's 2 day's work = 1/10? Please explain the step.
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.
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.
Emiley said:
9 years ago
A can do apiece of work in 30 days. B in 50 days and C in 40 days. If A is assisted by B on one day and by C on the next day alternately work will be completed in?
Sangeetha said:
9 years ago
@Nikitha.
Superb explanation.
Superb explanation.
Pavankushoba said:
9 years ago
Hi everyone here is my solution.
According to problem (a + b + c) 1 day work = 1/10.
As per the problem A is assisted by B and C every third day so first let us find,
Work done by A in 2 days = 1/20 * 2 = 1/10.
As mentioned in step 3 B and C are assisted on the third day.
(So A's 2-day work, And one important point A also work along with B and C on third day = 1/10 + (1/20 + 1/30 + 1/60) = 1/5.
Its 3 days work done by A B and C = 1/5.
1-day work = x (assume).
By cross multiplication.
We get 3x = 1/5.
x = 1/15.
So its 15 days thank you.
According to problem (a + b + c) 1 day work = 1/10.
As per the problem A is assisted by B and C every third day so first let us find,
Work done by A in 2 days = 1/20 * 2 = 1/10.
As mentioned in step 3 B and C are assisted on the third day.
(So A's 2-day work, And one important point A also work along with B and C on third day = 1/10 + (1/20 + 1/30 + 1/60) = 1/5.
Its 3 days work done by A B and C = 1/5.
1-day work = x (assume).
By cross multiplication.
We get 3x = 1/5.
x = 1/15.
So its 15 days thank you.
PARSHU said:
9 years ago
3 values there 3persons working to gather assisted A's B + C we calculate A + B + C/2 we get,
A+ B + C = 1/20 + 1/30 + 1/60.
LCM denomineor = 1/10 = 10 * 3 total 30/2 = 15-> 3persons work.
A+ B + C = 1/20 + 1/30 + 1/60.
LCM denomineor = 1/10 = 10 * 3 total 30/2 = 15-> 3persons work.
Subash said:
9 years ago
In 3 days they work is 1/5;
Then remaining work is 1 - 1/5 = 4/5,
So using proportions 1/5 : 45 :: 3 : x.
Get 12days.
+ 3days = 15days.
Then remaining work is 1 - 1/5 = 4/5,
So using proportions 1/5 : 45 :: 3 : x.
Get 12days.
+ 3days = 15days.
Sid said:
9 years ago
According to me, the answer is [1/10 + 1/10 + 1/20] = 1/4 for 3 days the whole days is 4 * 3 = 12.
Harsha said:
9 years ago
According to the question the A has been assisted by B and C after the third day.
It means the A has to work for three days and the third day is followed by B and C.
It means the A has to work for three days and the third day is followed by B and C.
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