Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 7)
7.
A can do a piece of work in 4 hours; B and C together can do it in 3 hours, while A and C together can do it in 2 hours. How long will B alone take to do it?
Answer: Option
Explanation:
| A's 1 hour's work = | 1 | ; |
| 4 |
| (B + C)'s 1 hour's work = | 1 | ; |
| 3 |
| (A + C)'s 1 hour's work = | 1 | . |
| 2 |
| (A + B + C)'s 1 hour's work = |  |
1 | + | 1 |  |
= | 7 | . |
| 4 | 3 | 12 |
| B's 1 hour's work = | |
7 | - | 1 | |
= | 1 | . |
| 12 | 2 | 12 |
B alone will take 12 hours to do the work.
Discussion:
100 comments Page 9 of 10.
Sireesha said:
1 decade ago
[(b+c)=1/3]-[(a+c)=1/2]
=> b=1/12
=>b's time= 12hrs
=> b=1/12
=>b's time= 12hrs
SAI said:
1 decade ago
B = A+ (B+C) - (A+C) = 1/4 + 1/3 -1/2 = 1/12.
B = 12.
B = 12.
Sohail said:
7 years ago
How, (7/12 - 1/2) = 1/12?
Explain this step please.
Explain this step please.
Ashish said:
2 decades ago
Good question. Reasoning is difficult for this one.
Arumugam said:
5 years ago
A = 1/4,
A+b = 1/3.
B = 1/3-1/4 = 1/12.
And = 12.
A+b = 1/3.
B = 1/3-1/4 = 1/12.
And = 12.
(6)
Abhin said:
1 decade ago
By the way why we are reciprocating 1/12 into 12?
Shree said:
8 years ago
Clear and detailed explanation. Thank you all.
Anjum said:
10 years ago
Thank you everyone for the clear explanation.
Chiru said:
10 years ago
Thank you everyone for the clear explanation.
Mohit said:
1 decade ago
Why its taken 1/4 and 1/3 ? 4 and 3 why not?
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