Question

A can lay railway track between two given stations in 16 days and b can do the same job in 12 days. With help of c, they did the job in 4 days only. Then, c alone can do the job in: a. 9 1 days 5 b. 9 2 days 5 c. 9 3 days 5 d. 10 [#

Answer 1

Answer:

option c   9$\frac{3}{5}$

Step-by-step explanation:

A can lay railway track between two given stations in 16 days

A's 1 day work = 1/16

B can lay railway track between two given stations in 12 days

B's 1 day work = 1/12

Let Say C can lay railway track between two given stations in x days

C's 1 day work = 1/x

A + B + C's  1 day work = 1/16 + 1/12  + 1/x

A + B + C's  4 day work  = 4 ( 1/16 + 1/12  + 1/x)

A + B + C completed work in 4 days

4 ( 1/16 + 1/12  + 1/x)  = 1

Multiplying by 48x both sides

4 * (3x + 4x + 48) = 48x

7x + 48 = 12x

48 = 5x

x = 48/5

x = 9$\frac{3}{5}$

option c

Answer 2

Answer=Option C)

Explanation/Solution

Amount of work A can do in 1 day = 1/16

Amount of work B can do in 1 day = 1/12 

Amount of work A, B and C can together do in 1 day = 1/4

Amount of work C can do in 1 day = 1/4 - (1/16 + 1/12) = 3/16 – 1/12 = 5/48

=>Hence C can do the job on 48/5 days = 9 whole (3/5) days