Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 22)
22.
A and B can complete a work in 15 days and 10 days respectively. They started doing the work together but after 2 days B had to leave and A alone completed the remaining work. The whole work was completed in :
Answer: Option
Explanation:
| (A + B)'s 1 day's work = |  |
1 | + | 1 |  |
= | 1 | . |
| 15 | 10 | 6 |
| Work done by A and B in 2 days = | |
1 | x 2 | |
= | 1 | . |
| 6 | 3 |
| Remaining work = | |
1 - | 1 | |
= | 2 | . |
| 3 | 3 |
| Now, | 1 | work is done by A in 1 day. |
| 15 |
 |
2 | work will be done by a in | |
15 x | 2 | |
= 10 days. |
| 3 | 3 |
Hence, the total time taken = (10 + 2) = 12 days.
Discussion:
40 comments Page 2 of 4.
Deepak kumar said:
7 years ago
A=15.
B=10.
Total work 30.
One day A Work 2.
One day B work 3.
So 2 days together work 5*2=10.
So remaining work 30-10 =20.
20/2= 10.
10+2= 12 days answer.
B=10.
Total work 30.
One day A Work 2.
One day B work 3.
So 2 days together work 5*2=10.
So remaining work 30-10 =20.
20/2= 10.
10+2= 12 days answer.
(1)
Banodai said:
8 years ago
This problem as it is 11th problem.
B did work 2 days out of 10 days = 2/10 = 1/5.
Remaining work = 1-1/5 = 4/5.
A did 1/15 th work in 1 day.
A did 4/5 th work in ? days.
Cross multiply,
? days = 4/5* 15= 12 days.
B did work 2 days out of 10 days = 2/10 = 1/5.
Remaining work = 1-1/5 = 4/5.
A did 1/15 th work in 1 day.
A did 4/5 th work in ? days.
Cross multiply,
? days = 4/5* 15= 12 days.
Pushpendra said:
8 years ago
I think your method was correct & easy. Thanks @Masud.
Bharathi said:
8 years ago
The work done 6 * 2 = 12 days.
Sunil said:
9 years ago
Why we have to add 2 in the last?
Masud said:
9 years ago
Work per day:
A = 1/15.
B = 1/10.
A work T day = T/15.
B work 2 day = 2/10,
(T/15 + 2/10) = 1.
2T + 6 = 30,
T = 12.
A = 1/15.
B = 1/10.
A work T day = T/15.
B work 2 day = 2/10,
(T/15 + 2/10) = 1.
2T + 6 = 30,
T = 12.
Divya said:
9 years ago
How 1/6 came?
Rushil said:
9 years ago
@Kala.
If 20 units are remaining then how you can do 20/2 because A had to do all work. So can you explain me that portion?
If 20 units are remaining then how you can do 20/2 because A had to do all work. So can you explain me that portion?
Kala said:
9 years ago
A -15days
B -10days
LCM - 30
A - 2unit/day
B - 3unit/day
A + B = 5unit/day
They worked for 2days, so 2 * 5 = 10,
Remaining 10 - 30 = 20,
A alone do the remaining in 20 ÷ 2 = 10,
So the total work get completed in 10 + 2 = 12,
Bcoz Already A+B worked for 2days,now A alone in 10 days.
B -10days
LCM - 30
A - 2unit/day
B - 3unit/day
A + B = 5unit/day
They worked for 2days, so 2 * 5 = 10,
Remaining 10 - 30 = 20,
A alone do the remaining in 20 ÷ 2 = 10,
So the total work get completed in 10 + 2 = 12,
Bcoz Already A+B worked for 2days,now A alone in 10 days.
(2)
Raja said:
9 years ago
Guys at last 2 are added. Look at questions carefully. Because the total time to complete the work is asked. Not time is taken by a to complete the job. So total day is 10 + 2=12.
Hope you are done what it now! Cheers.
Hope you are done what it now! Cheers.
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