Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 26)
26.
A and B can do a work in 8 days, B and C can do the same work in 12 days. A, B and C together can finish it in 6 days. A and C together will do it in :
Answer: Option
Explanation:
| (A + B + C)'s 1 day's work = | 1 | ; |
| 6 |
| (A + B)'s 1 day's work = | 1 | ; |
| 8 |
| (B + C)'s 1 day's work = | 1 | . |
| 12 |
 (A + C)'s 1 day's work |
|
||||||||||||||
|
|||||||||||||||
|
|||||||||||||||
|
So, A and C together will do the work in 8 days.
Discussion:
54 comments Page 3 of 6.
Rohit kushwaha said:
8 years ago
Thank you @Bhanu.
Nav said:
8 years ago
Why can't we simply subtract A+B's 1-day work from B+C's 1-day work to get A+C's 1-day work?
Ricky nahar said:
8 years ago
@Nandhu.
Why a=2?
Why a=2?
Setu kumar said:
1 decade ago
How we have taken (2*1/6)?
Rehan said:
8 years ago
(A+B)+(B+C)+(C+A) = 2 (A+B+C).
1/8 + 1/12+ (C+A) = 2 * 1/6.
1/8 + 1/12+ (C+A) = 2 * 1/6.
PRASHANT VERMA said:
7 years ago
1/8+1/12-1/6=1/24.
BECAUSE A+B = 8
B+C = 12
A+C = ?
A+B+C = 6.
BECAUSE A+B = 8
B+C = 12
A+C = ?
A+B+C = 6.
Pandeswari Durai Pandi said:
6 years ago
@Nanthu.
Thank you for using LCM method it makes me to understand it easily.
Thank you for using LCM method it makes me to understand it easily.
Rushikesh Shete said:
2 weeks ago
For those who did not understand how A+C is directly calculated in the solution. the trick is
we have A+B, B+C.
So,
LHS:
2(A+B+C)-(A+B)(B+C) = A + C.
Therefore, (A + C)'s 1 day's work.
RHS:
= (2 x 1/6) - (1/8 + 1/12) = 1/8.
we have A+B, B+C.
So,
LHS:
2(A+B+C)-(A+B)(B+C) = A + C.
Therefore, (A + C)'s 1 day's work.
RHS:
= (2 x 1/6) - (1/8 + 1/12) = 1/8.
Dhanshree said:
1 decade ago
(A+B) work is = 1/8.
(B+C)work is = 1/12.
(A+B+C)work is = 1/6.
Only A's work = 1/6-1/12
= 1/12.
Only C's work=1/6-1/8
= 1/24.
Hence (A+C)'s complete work is = (1/12+1/24)
= 1/8.
(A+C)'s complete work in 8 day.
(B+C)work is = 1/12.
(A+B+C)work is = 1/6.
Only A's work = 1/6-1/12
= 1/12.
Only C's work=1/6-1/8
= 1/24.
Hence (A+C)'s complete work is = (1/12+1/24)
= 1/8.
(A+C)'s complete work in 8 day.
Bhanu said:
2 decades ago
(A + B + C)'s 1 day's work = 1/6
(A + B)'s 1 day's work = 1/8
(B + C)'s 1 day's work = 1/12
so c's 1 day's work=1/6-1/8=1/24
and a's 1 day's work=1/6-1/12=1/12
and b's 1 day work=1/6(1/24+1/12)=1/4
so a and c 1'day work=1/12+1/24=1/8
(A + B)'s 1 day's work = 1/8
(B + C)'s 1 day's work = 1/12
so c's 1 day's work=1/6-1/8=1/24
and a's 1 day's work=1/6-1/12=1/12
and b's 1 day work=1/6(1/24+1/12)=1/4
so a and c 1'day work=1/12+1/24=1/8
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers