# 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:

89 comments Page 1 of 9.
Vijay said:
1 month 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.

(3)

Hemaharshini said:
11 months 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.

(30)

Jagadish Behera said:
2 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.

(43)

Dhananjay said:
2 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)

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.

(9)

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:
3 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:
3 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.

(13)

Aman Jadhao said:
3 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)

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