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 3 of 4.
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.
Inna Reddy Chilakala said:
10 years ago
A = 15.
B = 10.
After 2 days B had to leave.
X/15+2/10 = 1.
2X+6 = 30.
2X = 24.
X = 12.
B = 10.
After 2 days B had to leave.
X/15+2/10 = 1.
2X+6 = 30.
2X = 24.
X = 12.
Donald Trump said:
4 years ago
A = 15 = 1/15.
B = 10 =1/10.
1/10 * 2 =1/5.
1-1/5 = 4/5.
1/15 * 4/5 = 12 days.
B = 10 =1/10.
1/10 * 2 =1/5.
1-1/5 = 4/5.
1/15 * 4/5 = 12 days.
(3)
Bhaskar said:
1 decade ago
(2/10+2/15) +x/15=1.
Gives x=10.
Hence total days= 10+2=12 Answer.
Gives x=10.
Hence total days= 10+2=12 Answer.
Pushpendra said:
8 years ago
I think your method was correct & easy. Thanks @Masud.
Abdu Razak said:
10 years ago
Here B done 20%.
So A have to do 80 %.
80 % of 15 = 13.
So A have to do 80 %.
80 % of 15 = 13.
Vinisha said:
1 decade ago
Why is it 10+2 in the end? why is the 2 days added?
Vidya said:
1 decade ago
Thanks to say another method to me. Keep it up.
Aakansha Goyal said:
5 years ago
Why we add 2 for A's work? Explain please.
(3)
Sunil said:
9 years ago
Why we have to add 2 in the last?
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