Sami, one awesome money-monger, invested a certain sum of money in a simple interest bond whose value grew to Tk. 300 at the end of 3 years and to Tk. 400 at the end of another 5 years. What was the rate of interest in which he invested his sum?
Explanation: ধরি, Principal = tk. X তখন , দ্বিতীয় ক্ষেত্রে, interest = \(400-300 = Tk. 100\) এবং rate of interest = \(\frac{100}{5} = Tk. 20\) এই সুদের হারকে প্রথম ক্ষেত্রে ব্যবহার করে, ৩ বছরের interest = \(3 \times 20 = Tk. 60\) অর্থাৎ , principal = \(300-60 = Tk. 240\) তখন , actual rate of interest = \(\frac{60 \times 100}{240 \times 3} = Tk. 8.33\)]
