Solving the following mathematical problems:

Given, total students = 70

M=40; P= 35; C = 30  [Using first alphabet of all subjects]

P+C+M=15

Now, we can solve it by using Venn diagram. Let depict it.

We let the number of students

who study exactly two subjects are x, y & z. 

We have to find out the value of (x + y + z)

According to the question

$$\begin{gathered} 40-15-x-y+35-15-x-z+30-15-y-z+x+y+z+15=70 \\ \Rightarrow 105-30-x-y-z=70 \\ \Rightarrow 75-70=x+y+z \\ x+y+z=5 \end{gathered}$$
The number of students studying exactly two subjects is 5. 

Repeat: BDBL (SO) 2018 

His salary in 2014 was 20,000 Tk. per month.

 His salary in 2015 was = $\left(20000 + 20000\times \frac{10}{100}\right)= 22,000$ Tk. per month
100
His total income in 2015 was = $22,000\times 12 =2,64,000$ Tk.

 Again, his salary in 2016 was = $22000+22000\times \frac{10 }{100}= 24,200$ Tk.  per month 

His total income in 2016 was = $24,200\times 12= 2,90,400$ Tk. 

And, his salary in 2017 was = $\left(24200+ 24200\times \frac{10}{100}\right)= 26,620$ Tk. per month 

His total income in 2017 was = $26,620\times 12 = 3,19,440$ Tk. 

His total income from 2015 to 2017 was = $2,64,000+2,90,400+3,19,440=8,73,840$ Tk.

Repeat: BDBL (SO) 2018

Repeat: BDBL (SO)2018 

Repeat: BKB (Officer - Cash)  2018