The difference between the Compound Interest (compounded annually) and the Simple Interest on a certain sum at 10% per annum for 2 years is $15. Find the principal sum.
Rubina could get equal number of Rs. 55, Rs. 85 and Rs.105 tickets for a movie. She spends Rs. 2940 for all the tickets. How many of each did she buy?
In a collection of coins, the ratio of the number of 2-rupee coins to 5-rupee coins to 1-rupee coins is \(3 : 4 : 5\). If the total value of these coins is Rs. 18.75, how much money is represented by the 5-rupee coins?