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 4 of 10.
Raj said:
1 decade ago
Hi friends, my explanation.
A=1/4.
B and C Compain to work in 3 hours.
so B+C=1/3.
A and C compain to work in 2 hours.
so, A+C=1/2.
Put a=1/4.
1/4+c=1/2.
c=1/4.
B+C=1/3.
1/4+C=1\3.
C=12.
A=1/4.
B and C Compain to work in 3 hours.
so B+C=1/3.
A and C compain to work in 2 hours.
so, A+C=1/2.
Put a=1/4.
1/4+c=1/2.
c=1/4.
B+C=1/3.
1/4+C=1\3.
C=12.
Karthik said:
1 decade ago
A = 1/4.
B&C = 1/3.
A&C = 1/2.
1ST We have to find (A+B+C) therefore (1/4+1/3) = 7/12.
This for total work.
Now we subtract (A&C) value from 7/12.
7/12-1/2=1/12 take reciprocal for that value.
B&C = 1/3.
A&C = 1/2.
1ST We have to find (A+B+C) therefore (1/4+1/3) = 7/12.
This for total work.
Now we subtract (A&C) value from 7/12.
7/12-1/2=1/12 take reciprocal for that value.
Saleem said:
1 decade ago
Hi.
A = 1/4....(1).
B+C = 1/3....(2).
A+C = 1/2....(3).
Now solve equation (1) & (3).
1/4+C = 1/2.
C = 1/4....(4).
Put C value in equation (2).
B+1/4 = 1/3.
B = 1/3-1/4.
B = 1/12 that's the answer.
A = 1/4....(1).
B+C = 1/3....(2).
A+C = 1/2....(3).
Now solve equation (1) & (3).
1/4+C = 1/2.
C = 1/4....(4).
Put C value in equation (2).
B+1/4 = 1/3.
B = 1/3-1/4.
B = 1/12 that's the answer.
Kartik said:
1 decade ago
a = 1/4 B+c = 1/3 a+c = 1/2 on subtracting b+c = 1/3 & a+c = 1/2 we got,
b-a = -1/6 and a = 1/4 (given) on putting these value we got b=12 is 1 day work so now total is 12 days.
It's Very Simple.
b-a = -1/6 and a = 1/4 (given) on putting these value we got b=12 is 1 day work so now total is 12 days.
It's Very Simple.
Jagadish Behera said:
3 years ago
DATA GIVEN:
A=4hrs
B+C=3hrs
A+C=2hrs.
B=?
Ans: Total work =12
A = 3work
B+C = 4work
A+C = 6work
A+C = 6.
3 + C = 6
C=6-3 = 3 WORK.
B+C=4
B=4-3=1
So, that B alone whole work in 12/1 = 12 hrs.
A=4hrs
B+C=3hrs
A+C=2hrs.
B=?
Ans: Total work =12
A = 3work
B+C = 4work
A+C = 6work
A+C = 6.
3 + C = 6
C=6-3 = 3 WORK.
B+C=4
B=4-3=1
So, that B alone whole work in 12/1 = 12 hrs.
(54)
Bits said:
8 years ago
A in 4hrs.
B+C _ 3.
A+C _ 2.
Total work by taking lcm of 4,3,2 is 12units.
A in one day do = 12/4= 3.
A+C_ 6.
So C=3.
In the same way,
B+C= 12/3 > 4.
So B=1.
At last B =12/1=12. That's the answer!.
B+C _ 3.
A+C _ 2.
Total work by taking lcm of 4,3,2 is 12units.
A in one day do = 12/4= 3.
A+C_ 6.
So C=3.
In the same way,
B+C= 12/3 > 4.
So B=1.
At last B =12/1=12. That's the answer!.
(1)
Sai mounika said:
1 decade ago
It is easy to find out.
A+C = 1/2, A = 1/4.
(A+C) - A = 1/4 we got C = 1/4.
We know B+C = 1/3 then substitute C = 1/4 value here then we will get 1/12.
Hence B takes 12 hrs to complete the work.
A+C = 1/2, A = 1/4.
(A+C) - A = 1/4 we got C = 1/4.
We know B+C = 1/3 then substitute C = 1/4 value here then we will get 1/12.
Hence B takes 12 hrs to complete the work.
Kumar said:
1 decade ago
A =1/4 (A's ONE HOUR WORK)
B+C =1/3 (B+C's ONE HOUR WORK)
A+C =1/2 (A+C's ONE HOUR WORK)
C =1/2-A
B+1/2-1/4=1/3 (submitting c value in b+c=1/3 for value of b)
B=1/3-1/2+1/4
B=1/12
B+C =1/3 (B+C's ONE HOUR WORK)
A+C =1/2 (A+C's ONE HOUR WORK)
C =1/2-A
B+1/2-1/4=1/3 (submitting c value in b+c=1/3 for value of b)
B=1/3-1/2+1/4
B=1/12
SIDHARTH said:
1 decade ago
A'S 1 hr work = 1/4.
(B's+ C's) 1hr work = 1/3.
Therefore, (A+B+C's)1 hr work = 1/4+1/3 = 7/12.
Therefore, B's 1hr work = 7/12 - 1/2 = 1/12.
Hence B takes 12 hrs to complete the work.
(B's+ C's) 1hr work = 1/3.
Therefore, (A+B+C's)1 hr work = 1/4+1/3 = 7/12.
Therefore, B's 1hr work = 7/12 - 1/2 = 1/12.
Hence B takes 12 hrs to complete the work.
Yogesh H B said:
1 decade ago
A's 1hr work= 1/4......(1).
B+C=1/3.....(2).
A+C=1/2.......(3).
Solve eqn 1 and 3, we get,
C=1/4.
Put value of C in eqn (2), we get,
B=1/12.
So, B can finish a work in 12 days.
B+C=1/3.....(2).
A+C=1/2.......(3).
Solve eqn 1 and 3, we get,
C=1/4.
Put value of C in eqn (2), we get,
B=1/12.
So, B can finish a work in 12 days.
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