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 4 of 4.
Vinisha said:
1 decade ago
This sum is when B leaves after 2 days, but what is the statement was "B leaves 2 days before the completion of the work? How do you do it?
Vinisha said:
1 decade ago
Why is it 10+2 in the end? why is the 2 days added?
Chinna said:
1 decade ago
A's 1 day work = 1/15.
B = 1/10.
A+B = 1/15+1/10
= 1/6.
Remaining work = 1-1/6
= 5/6.
= 5/6*1/10.
= 12.
B = 1/10.
A+B = 1/15+1/10
= 1/6.
Remaining work = 1-1/6
= 5/6.
= 5/6*1/10.
= 12.
Arvind said:
1 decade ago
@Kapil.
Total work = 1.
A+B done in 2 days = 1/3.
So remaining = 1-1/3.
= 2/3 :) .
@Mr Aj. Good, well done.
Total work = 1.
A+B done in 2 days = 1/3.
So remaining = 1-1/3.
= 2/3 :) .
@Mr Aj. Good, well done.
Mr.AJ said:
1 decade ago
To make it even simple.
A = 1/15;B = 1/10;
B works 2 days = 2/10;
A works y days = y/15;
=>y/15+2/10 = 1.
=>y/15 = 4/5.
So y =12; done.
A = 1/15;B = 1/10;
B works 2 days = 2/10;
A works y days = y/15;
=>y/15+2/10 = 1.
=>y/15 = 4/5.
So y =12; done.
Kapil said:
1 decade ago
How 2/3 came?
Ranjith said:
1 decade ago
A=100/15=6.66%
B=100/10=10%
B=100/10=10%
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.
Vidya said:
1 decade ago
Thanks to say another method to me. Keep it up.
Ghousia said:
1 decade ago
A's 1 day work=1/15
B's 1 day work=1/10
now,B left after 2 days then 1/10*2=1/5
remaining work is (1-1/5)=4/5
4/5 work is left by B then A has to do remaining work (1/15*5/4)=1/12 this is A's 1 day work after B left work
now A completes work in 12 days...
B's 1 day work=1/10
now,B left after 2 days then 1/10*2=1/5
remaining work is (1-1/5)=4/5
4/5 work is left by B then A has to do remaining work (1/15*5/4)=1/12 this is A's 1 day work after B left work
now A completes work in 12 days...
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