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:
95 comments Page 2 of 10.
Spoorti said:
3 years ago
Thank you @Bhanu.
(3)
Bhanu said:
3 years ago
A = 1/4
A + C = 1/2 ---> eq1
B + C = 1/3 ---> eq2.
Substitute a = 1/4 in eq1.
C = 1/2-1/4
C = 1/4.
Sub C=1/4 in eq 2.
B+C=1/3.
B = 1/3-1/4.
= 1/12.
= 12 days.
A + C = 1/2 ---> eq1
B + C = 1/3 ---> eq2.
Substitute a = 1/4 in eq1.
C = 1/2-1/4
C = 1/4.
Sub C=1/4 in eq 2.
B+C=1/3.
B = 1/3-1/4.
= 1/12.
= 12 days.
(10)
Arumugam said:
3 years ago
A = 1/4,
A+b = 1/3.
B = 1/3-1/4 = 1/12.
And = 12.
A+b = 1/3.
B = 1/3-1/4 = 1/12.
And = 12.
(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)
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)
Aman Jadhao said:
4 years ago
Hi;
a=4h
B+c=3h
A+c=2h
B=?.
A b+c. A+c
4. 3 2
Take LCM of
Lcm=12
After LCM value is
3. 4. 6.
Adding the value we get
A + c = 2
C = 1.
Then solve
B+c =4,
B=3.
Simply multiple with LCM values of b&c
3 * 4 = 12 hours.
a=4h
B+c=3h
A+c=2h
B=?.
A b+c. A+c
4. 3 2
Take LCM of
Lcm=12
After LCM value is
3. 4. 6.
Adding the value we get
A + c = 2
C = 1.
Then solve
B+c =4,
B=3.
Simply multiple with LCM values of b&c
3 * 4 = 12 hours.
(3)
Pallabi Sethi said:
4 years ago
A 1 hours work=1/4 ----> (i)
B+C 1 hors work=1/3 ----> (ii)
A+C 1 hour work=1/2 ----> (iii).
By subtracting from (iii) to (ii) we get A-B = 1/6.
Now in place of A put the value of A = 1/4.
1/4-B = 1/6,
1/4-1/6 = B.
1/12 IS B'S 1 Hour's work.
B will take 12 hours.
B+C 1 hors work=1/3 ----> (ii)
A+C 1 hour work=1/2 ----> (iii).
By subtracting from (iii) to (ii) we get A-B = 1/6.
Now in place of A put the value of A = 1/4.
1/4-B = 1/6,
1/4-1/6 = B.
1/12 IS B'S 1 Hour's work.
B will take 12 hours.
Abhimanyu said:
4 years ago
A = 4 B + C = 3 A + C = 2.
(B+C) - (A+C) + A = B(Making equation such that we will get value of B)
1/3 -1/2 + 1/4 = B.
B = 4 - 6 + 3/12(By taking kam) = 1/12.
B = 12.
(B+C) - (A+C) + A = B(Making equation such that we will get value of B)
1/3 -1/2 + 1/4 = B.
B = 4 - 6 + 3/12(By taking kam) = 1/12.
B = 12.
Don said:
4 years ago
How 7/12 - 1/2 = 1/12? Explain this.
Lazy Balu said:
5 years ago
A+(B+C)-(C+A) = 1/4+1/3-1/2.
A+B+C-C-A = (3+4-6)/12.
Therefore B = 1/12.
So B can do in 12 days.
A+B+C-C-A = (3+4-6)/12.
Therefore B = 1/12.
So B can do in 12 days.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers