Time & Work Practice Set 2nd Solution

Here I am presenting you the solution of Time & Work - Practice Set 2^nd .

Q21. Ram and Shyam together can finish a job in 8 days. Ram can do the same job on his own in 12 days. How long will Shyam take to do the job by himself?

(a) 16 days              (b) 20 days               (c) 24 days              (d) 30 days

Sol. Let shyam takes x days to complete the work.

According to the Concept

1/12 + 1/x = 1/8.

1/x = 1/8 – 1/12

1/x = 1/24.

x = 24 days.  

Answer option (a)

Q22. A and B together can complete a piece of work in 12 days, B and C can do it in 20 days and C and A can do it in 15 days. A, B and C together can complete it in how many days?

(a) 6 days       (b) 10 days      (c) 12 days             (d) 20 days 

Sol. One day work details:

A + B → 1/12.

B + C → 1/20.

C + A → 1/15.

On adding 2(A + B + C) → 1/12 + 1/20 + 1/15

2(A + B + C) → 12/60.

2(A + B + C) → 1/5.

A + B + C → 1/10.

Hence A, B and C can complete the work in 10 days.

Answer option (b)

Q23. A and B together can complete a piece of work in 8 days while B and C together can do it in 12 days. All the three together can complete the work in 6 days. In how much time will A and C together complete the same work?

(a) 8 days            (b) 10 days            (c) 12days        (d) 20 days

Sol. One day work details:

A + B → 1/8.                    .............................. eq.no. (i)

B + C → 1/12.              ............................... eq.no.(ii)

A + B + C → 1/6.          ............................... eq.no.(iii)

Eq.no. (i) + eq.no. (ii)

A + 2B + C → 5/24.      ............................. eq.no.(iv)

Eq.no. (iv) – eq.no. (iii)

B → 5/24 – 1/6

B → 1/24.                       ............................. eq.no.(v)

Eq.no. (iii) – eq.no. (v)

A + C → 1/6 – 1/24.

A + C → 3/24.

A + C → 1/8.

Hence A and C can complete the work in 8 days.

Answer option (a)

Q24. A man, a women and a boy together complete a piece of work in 3 days. If a men alone can do it in 6 days and a boy alone in 18 days, how long a women will take to complete the work?

(a) 9 days     (b) 21 days         (c) 24 days           (d) 27 days

Sol. Let woman takes x days to complete the work.

According to the Concept

1/6 + 1/x + 1/18 = 1/3.

1/x = 1/3 – 2/9

1/x = 1/9.

x = 9 days.  

Answer option (a)

The solution continues in the next post on the blog, just check it...................