A sum was put at simple interest at a certain rate for 10 years . Had it been put at 5% higher rate , it would have fetched Rs.600 more. What was the Sum?
Select the correct option.
A) rs . 1200  B) rs . 1300  C) rs . 1400  D) rs . 1500  E) none of these

Rationale: "explanation : at 5 % more rate , the increase in s . i for 10 years = rs . 600 ( given ) so , at 5 % more rate , the increase in si for 1 year = 600 / 10 = rs . 60 / - i . e . rs . 60 is 5 % of the invested sum so , 1 % of the invested sum = 60 / 5 therefore , the invested sum = 60 × 100 / 5 = rs . 1200 answer : a"
Answer: A