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 :
4 days
6 days
8 days
12 days
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

Therefore (A + C)'s 1 day's work
= ( 2 x 1 ) - ( 1 + 1 )
6 8 12
= ( 1 - 5 (
3 24
= 3
24
= 1 .
8

So, A and C together will do the work in 8 days.

Discussion:
53 comments Page 1 of 6.

Nandakumar said:   1 decade ago
How can i take 2*1/8-(1/8+1/12)?

Bhanu said:   1 decade 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

Akiii said:   1 decade ago
Good explanation.

Azuu said:   1 decade ago
How to take lcm of 1/8+1/12 ?

Sabarimani said:   1 decade ago
Is b's 1day work=1/6-(1/24+1/12)?

Gulshan said:   1 decade ago
24 is lcm of 8 & 12

Kavitha said:   1 decade ago
Why did you take 1/6 (1/12+1/24) ?

Anishkumar said:   1 decade ago
Assume A+C as x

so now
2(A+B+C)=1/8+1/12+1/x


2(1/6) =5/24+1/x

finally

x =8

Parveen verma said:   1 decade ago
(A+B+C)=1/6
A's one day work work= (A+B+C)-(B+C)= 1/6-1/12 =1/12
C's one day work work= (A+B+C)-(A+B)= 1/6-1/8= 1/24
(A+C)'s one day work= 1/12+1/24= 1/8
so the work will be completed in 8 days

Sujeet said:   1 decade ago
Why 2 is multiplied by 1/6.


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