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:
97 comments Page 8 of 10.
NARESH PAL said:
10 years ago
(A + B) - B = B + C (A and B, C works equal).
1/10 - B = B + C.
1/2B = 1/10 - 1/50.
B = 25.
1/10 - B = B + C.
1/2B = 1/10 - 1/50.
B = 25.
Lakshmi said:
1 year ago
A --->1/4.
A+B -->1/3.
(A+B)-A -->1/3-1/4.
= 1/12.
B alone 12 hours.
A+B -->1/3.
(A+B)-A -->1/3-1/4.
= 1/12.
B alone 12 hours.
(16)
Sagar raut said:
10 years ago
A's 1 day work is 1/4.
A and B 1 day work is 1\3.
So 1/(A+B)-1\A = 1\B.
1\3 - 1\4 = 1\12.
A and B 1 day work is 1\3.
So 1/(A+B)-1\A = 1\B.
1\3 - 1\4 = 1\12.
Vijay said:
1 year ago
(B+C)-(A+C) = (B-A).
(B-A)+(A) = B.
1/3-1/2+1/4= 4/12 - 6/12 + 3/12 = 1/12.
= 12 hrs.
(B-A)+(A) = B.
1/3-1/2+1/4= 4/12 - 6/12 + 3/12 = 1/12.
= 12 hrs.
(6)
Ankur said:
1 decade ago
B+C=1/3
A+C=1/2
A+C-(B+C)=1/2-1/3
A-B=1/6
B=A-1/6
B=1/4-1/6
B=1/12
ie 12 is the ans
A+C=1/2
A+C-(B+C)=1/2-1/3
A-B=1/6
B=A-1/6
B=1/4-1/6
B=1/12
ie 12 is the ans
Sainath said:
1 decade ago
a=1/4
a+c=1/2
c=1/2-a
c=1/4
: b+c=1/3
b=1/3-c
b=1/12
b can do it in 12 days....
a+c=1/2
c=1/2-a
c=1/4
: b+c=1/3
b=1/3-c
b=1/12
b can do it in 12 days....
Ajay said:
10 years ago
For these type of questions,
Try to combine a+b+c and and evaluate each type.
Try to combine a+b+c and and evaluate each type.
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.
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