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 6 of 10.
Ashim said:
9 years ago
4A = 3 (B + C) = 2 (A + C).
4A = 2A + 2C, A = C.
3B + 3C = 2A + 2C.
3B = C.
Or 3B = A.
If A takes 4 hours to complete the work than B takes 12 hours.
4A = 2A + 2C, A = C.
3B + 3C = 2A + 2C.
3B = C.
Or 3B = A.
If A takes 4 hours to complete the work than B takes 12 hours.
Akshay Jaywant said:
9 years ago
Thanks to all of my friends giving the wonderful methods.
It's very simple.
A + (B + C) - (A + C) = B.
1/4 + 1/3 - 1/2 = 1/12.
Therefore, 12 hrs.
It's very simple.
A + (B + C) - (A + C) = B.
1/4 + 1/3 - 1/2 = 1/12.
Therefore, 12 hrs.
Nagendramurthy said:
1 decade ago
Hi friends,
(A+C-A)=C
(1/2-1/4)=1/4
so C's 1 hour work will be 1/4.
Similarly
(B+C-C)=B
(1/3-1/4)=1/12
Therefore B's 1 hour work is 1/12.
(A+C-A)=C
(1/2-1/4)=1/4
so C's 1 hour work will be 1/4.
Similarly
(B+C-C)=B
(1/3-1/4)=1/12
Therefore B's 1 hour work is 1/12.
Rohit said:
8 years ago
Guys!.
I simply subtracted the (A's) work - (B's+C's)work
so I got,
1/4-1/3=-1/12 for 1hour.
hence for b to do alone his work 12 hour.
I simply subtracted the (A's) work - (B's+C's)work
so I got,
1/4-1/3=-1/12 for 1hour.
hence for b to do alone his work 12 hour.
Namrata Gujar said:
4 years ago
A = 4
B+c = 3
A+c = 2.
Lcm office 4,3,2 is 12.
A+c = 2,
4+c = 2,
C = 4-2,
C = 2.
B+c = 3,
B+2 = 3,
B = 1.
Total work 12.
12*1 = 12.
B+c = 3
A+c = 2.
Lcm office 4,3,2 is 12.
A+c = 2,
4+c = 2,
C = 4-2,
C = 2.
B+c = 3,
B+2 = 3,
B = 1.
Total work 12.
12*1 = 12.
(14)
Avinash said:
1 decade ago
A's 1day wrk------>1/4
B+C's 1day wrk---->1/3
A+C's 1day wrk---->1/2
(A+C)-A=1/2-1/4=1/2 ie.. c=1/4
so B+1/4=1/3--->b=1/12
B+C's 1day wrk---->1/3
A+C's 1day wrk---->1/2
(A+C)-A=1/2-1/4=1/2 ie.. c=1/4
so B+1/4=1/3--->b=1/12
Prajwal said:
9 years ago
A = 1/4.
B + C= 1/3.
A + C= 1/2.
B = ?
C = 1/2 - A.
C = 1/2 - 1/4 = 1/4.
B = 1/3 - C.
B = 1/3 - 1/4.
B = 1/12.
B takes 12 hrs.
B + C= 1/3.
A + C= 1/2.
B = ?
C = 1/2 - A.
C = 1/2 - 1/4 = 1/4.
B = 1/3 - C.
B = 1/3 - 1/4.
B = 1/12.
B takes 12 hrs.
ARAVIND MATHALA said:
1 year ago
A = 1/4
B+C = 1/3
A+C = 1/2
B=?
C = (A+C)-A = > (1/2)-1/4 =>1/4,
B = (B+C)-C = >(1/3)-1/4 =>1/12.
Then B = 12 Hours.
B+C = 1/3
A+C = 1/2
B=?
C = (A+C)-A = > (1/2)-1/4 =>1/4,
B = (B+C)-C = >(1/3)-1/4 =>1/12.
Then B = 12 Hours.
(5)
Logesh said:
4 years ago
Simply, subs A's value in Eqn 1:
A + C= 1/2
C = 1/2-1/4
C = 1/4
Sub C's VALUE IN B+C = 1/3;
B = 1/3-1/4
B = 1/12 , we got it.
A + C= 1/2
C = 1/2-1/4
C = 1/4
Sub C's VALUE IN B+C = 1/3;
B = 1/3-1/4
B = 1/12 , we got it.
(2)
Arjun said:
1 decade ago
Total =4
b&c =3...1
a&c= 2...2
we have to find c so 1 c is 3 therefore 3*4=12
Hey guys let me know if i am correct.
b&c =3...1
a&c= 2...2
we have to find c so 1 c is 3 therefore 3*4=12
Hey guys let me know if i am correct.
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