1) Mr. Y gave some money at simple interest and at the end of 10 years, got back twice the sum. The rate percent per annum is A) 2% B) 4% C) 5% D) 10% E) 12% Answer: Option DExplanation:$P$ $=100$ becomes $200$ in $10$ years $SI$ $=100$ $R$ $=\frac{(100\times SI)}{P\times N}$ $=\frac{(100\times 100)}{(100\times 10)}$ = 10%
