A sum of money at simple interest amounts to Tk. 721 in 3 years and to Tk. 854 in 4 years. The sum is-

Question: A sum of money at simple interest amounts to Tk. 721 in 3 years and to Tk. 854 in 4 years. The sum is-

Solution:
Simple interest for 1 year = Tk. (854 - 721)
= Tk. 133

∴ Simple interest for 3 years = Tk.(133 × 3)
= Tk. 399

∴ Sum = (721 - 399)
= Tk. 322