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1.
The difference between simple and compound interest on a sum of money at 20% per annum for 3 years is Tk. 48. What is the sum ?
- A. Tk. 550
- B. Tk. 550
- C. Tk. 550
- D. Tk. 550
Answer: Option C
Explanation:
Let principal amount be Tk.100.
Then, S.I. = (100 × 20 × 3)/100 = Tk.60
and C.I. = 100 (1 + 20/100)^3−100
= 100 × (6/5)^3−100 = 364/5
∴ C.I. - S.I. = 364/5−60 = 64/5
If the difference is Tk.64/5, Principal = Tk.100
If difference is Tk.48
Principal = (100 × 5/64) × 48 = Tk.375
Then, S.I. = (100 × 20 × 3)/100 = Tk.60
and C.I. = 100 (1 + 20/100)^3−100
= 100 × (6/5)^3−100 = 364/5
∴ C.I. - S.I. = 364/5−60 = 64/5
If the difference is Tk.64/5, Principal = Tk.100
If difference is Tk.48
Principal = (100 × 5/64) × 48 = Tk.375
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