7
Q:

# A, B and C can complete a piece of work in 24,6 and 12 days respectively.Working together, they will complete the same work in:

 A) 1/24 days B) 7/24 days C) 24/7 days D) 4 days

Explanation:

(A+B+C)'s 1 day's work =$\inline&space;{\color{Black}\left&space;(&space;\frac{1}{24}+\frac{1}{6}+\frac{1}{12}&space;\right&space;)=\frac{7}{24}}$

so, A,B and C together will complete the work in 24/7 days.

Q:

A take twice as much time as B or thrice as much time to finish a piece of work. Working together, they can finish the work in 2 days. B can do the work alone in  ?

 A) 8 hrs B) 12 hrs C) 6 hrs D) 4 hrs

Explanation:

Suppose A, B and C take x, x/2 and x/3 respectively to finish the work.

Then, (1/x + 2/x + 3/x) = 1/2

6/x = 1/2 => x = 12

So, B takes 6 hours to finish the work.

1 1
Q:

Sixty men can stitch 150 shirts in 30 days working 8 hours a day. In how many days can 35 men stitch 200 shirts working 6 hours a day ?

 A) 87.5 B) 89 C) 91.5 D) 93.5

Explanation:

We have M1 D1 H1 / W1 = M2 D2 H2 / W2 (Variation rule)
(60 x 30 x 8)/ 150 = (35 x D2 x 6) / 200
D2 = (60 x 30 x 8 x 200) / (150 x 35 x 6) => D2 = 91.42 days =~ 91.5 days.

1 24
Q:

A can complete a piece of work in 12 days and B is 60% more efficient than A. In how many days B will complete the same work  ?

 A) 8.7 hrs B) 5.2 hrs C) 5 hrs D) 7.5 hrs

Explanation:

Ratio of times taken by A and B = 160 : 100
A can do the work in 12 days
Let B can do the work in "D" days
=> 160:100 = 12 : D
=> D = 12 x 100/160 = 7.5 hrs

2 50
Q:

A can finish a work in 18 days and B can do the same work in half the time taken by A. then, working together, what part of the same work they can finish in a day ?

 A) Total work B) One-fourth work C) Half work D) Two-third work

Explanation:

A can do the work = 18 days
B can do the work = 18/2 = 9 days
(A + B)'s 1 day work = 1/18 + 1/9 = 1/6
=> In 3 days = 3x1/6 = 1/2 work is completed.

1 35
Q:

10 boys can complete a work in 7 days and 10 girls take 14 days to complete the work. How many days will 5 boys and 10 girls take to complete the work ?

 A) 13 days B) 10 days C) 7 days D) 16 days