Shakil started a business investing tk. 25,000 in 2009 . In 2010 , he invested an additional amount of Tk. 10,000 and Raihan joined him with an amount if Tk. 35,000. In 2011 Shakil invested another additional amount of Tk, 10,000 and Jafor joined them with an amount of 35,000. What will be Raihan’s share in the profit of Tk. 1,50,000 earned at the end of 3 years from the start of the business in 2009. (Work and Time)

9 টি ইঞ্জিন দিনে 8 ঘন্টা করে কাজ করে 24 মেট্রিক টন কয়লা ব্যবহার করে। তাহলে 13 ঘন্টা করে কাজ করে 8 টি ইঞ্জিন কত মেট্রিক টন কয়লা ব্যবহার করবে যেখানে দেয়া আছে যে, প্রথম ক্ষেত্রের প্রতি 3 টি ইঞ্জিন পরবর্তী প্রতি 4 টি ইঞ্জিনের সমান কয়লা ব্যবহার করে? 

Given that, 4 engines of latter type = 3 engines of former type

So 8 engines of latter type=$\frac{3}{4}\times 8=6$ engines of former type

Now, In 8 hours 9 engines consume 24 metric tones

In 13 hours 6 engines consume =$\frac{24\times 13\times 6}{8\times 9}$ metric tones= 26 metric tones (ans)

Let, the amount invested in Scheme B = Tk. 100x 

So, the amount invested in Scheme C= Tk.$(100x \times 240\%)=Tk. 240x$

Here, the amount invested in Scheme C = 150% of the amount invested in Scheme A

$$\begin{gathered} \Rightarrow Tk. 24x= 150\times \frac{A}{100} \\ \Rightarrow A=TK. \frac{24,000}{150}=TK. 160x \end{gathered}$$

So, the amount invested in Scheme A= Tk. 160x

Now, Interest from Scheme A= Tk. $(160x \times 10\%) = Tk. 16x$

Interest from Scheme B= $Tk. (100x \times 12\%) = Tk.12x$

Interest from Scheme C = Tk.$(240x\times 15\%) = Tk.36x$

According to the question, 

$$\begin{gathered} 16x+12x+36x=3,200 \\ \Rightarrow 64x=3200 \\ \Rightarrow x=\frac{3200}{64} \\ \Rightarrow x=50 \\ \Rightarrow 100x=50\times 100 \\ \therefore 100x=5,000 \end{gathered}$$

So, the amount invested in Scheme B = Tk. 5000 ans.