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:
96 comments Page 9 of 10.
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)
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)
Arumugam said:
4 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.
(6)
Bhanu said:
4 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)
Spoorti said:
4 years ago
Thank you @Bhanu.
(3)
Dhananjay said:
3 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.
(7)
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)
Hemaharshini said:
2 years ago
A = 1/4 ---(1)
B + C = 1/3 ----(2)
A + C = 1/2----(3)
=>Sub (1) in (3)
1/4 + C =1/2
C=1/4 => one day work of C---- (4)
=> Now sub (4) in (2) to find b's one day's work.
B + 1/4 = 1/3.
B = 1/12
B = 12 hours.
B + C = 1/3 ----(2)
A + C = 1/2----(3)
=>Sub (1) in (3)
1/4 + C =1/2
C=1/4 => one day work of C---- (4)
=> Now sub (4) in (2) to find b's one day's work.
B + 1/4 = 1/3.
B = 1/12
B = 12 hours.
(40)
Vijay said:
1 year ago
(B+C)-(A+C) = (B-A).
(B-A)+(A) = B.
1/3-1/2+1/4= 4/12 - 6/12 + 3/12 = 1/12.
= 12 hrs.
(B-A)+(A) = B.
1/3-1/2+1/4= 4/12 - 6/12 + 3/12 = 1/12.
= 12 hrs.
(6)
NAVEEN CHIKATI said:
1 year ago
Hi,
A - 4.
B +C - 3.
A + C - 3.
LCM OF ALL -12
A = 12/4 = 3
B+C = 12/3 = 4
A+C = 12/2 = 6
B = ?.
TOTAL = (A) + (B+C) + (A+C),
= (3) + (4) + (6),
= 13.
TO FIND C= A + C = 6,
= 3 + c = 6,
C = 6 - 3,
C = 3.
TO FIND B = B + C = 4,
= B + 3 = 4,
B = 3 - 4,
B = 1.
B = 1/12.
B takes 12 hours.
A - 4.
B +C - 3.
A + C - 3.
LCM OF ALL -12
A = 12/4 = 3
B+C = 12/3 = 4
A+C = 12/2 = 6
B = ?.
TOTAL = (A) + (B+C) + (A+C),
= (3) + (4) + (6),
= 13.
TO FIND C= A + C = 6,
= 3 + c = 6,
C = 6 - 3,
C = 3.
TO FIND B = B + C = 4,
= B + 3 = 4,
B = 3 - 4,
B = 1.
B = 1/12.
B takes 12 hours.
(10)
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers