Jamuna Bank Ltd Recruitment Test for Probationary Officer Examination Held On : 20.10.2017 || 2017

$$\begin{gathered} Let, Total member is 10 \\ Now, according to the question \\ 10x-30\% of 10x=12+30 \\ \Rightarrow 10x-3x=12+30 \\ \Rightarrow 7x=42 \\ \therefore x=6 \\ Total mbembers=10x=10\times 6=60. \end{gathered}$$

Let, x marbles are there in box. 

Now, total capacity of the box= x+100

According to the question,

$$\begin{gathered} x-\frac{x}{4}=\frac{x+100}{3} \\ \Rightarrow \frac{4x-x}{4}=\frac{x+100}{3} \\ \Rightarrow \frac{3x}{4}=\frac{x+100}{3} \\ \Rightarrow 9x=4x+400 \\ \Rightarrow 5x=400 \\ \therefore x=\frac{400}{5}=80 \end{gathered}$$

There are 80 marbles in the box.

In 18 days, they can complete = 1 parts of work 

In 1 days, they can complete= $\frac{1}{18}$ parts of work

In 12 days, they can complete = $\frac{12}{18}=\frac{2}{3}$ parts of work 

Remaining work  $=\left(1-\frac{2}{3}\right)=\left(\frac{3-2}{3}\right)=\frac{1}{3}$

Now,$\frac{1}{3}$ parts of work is done by Alam in = 8 days 

1 or complete parts of work is done by Alam in= $8 \times 3 = 24 days$

Alam can do $\frac{1}{24}$ parts of work in 1 day.

Minhaz can do in 1 day =$\left(\frac{1}{18}-\frac{1}{24}\right)=\left(\frac{4-3}{72}\right)=\frac{1}{72}$ parts

That means $\frac{1}{72}$ parts of work is done by Minhaz in 1 day

1 or complete parts of work is done by Minhaz in $\frac{72\times 1}{1}=72 day$

He can do the whole work alone in 72 days. ans.