1)

12 children takes 16 days to complete a work which can be completed by 8 adult in 12 days. 16 adults started working and after 3 days,10 adults left and 4 children joined them. How many days will they take to complete the remaining work?


A) 3

B) 4

C) 6

D) 8

E) 9

Answer:

Option C

Explanation:

1 child 1 day work $=\frac{1}{192}$

1 adult 1 day work $=\frac{1}{96}$

Work done by 16 adults in 3 days $=\frac{1}{96}\times 16\times 3$ $=\frac{1}{2}$

Remaining work $=\left(1-\frac{1}{2}\right)$ $=\frac{1}{2}$.

(6 adult + 4 children ) 1 day work $=\left(\frac{6}{96}+\frac{4}{192}\right)$ $=\frac{1}{12}$

$\frac{1}{12}$ work is done by them in 1 day

 $\frac{1}{2}$ work is done by them $\left(12\times \frac{1}{2}\right)$ = 6 days