For the following questions answer them individually
A sum of money at 8% Simple Interest was placed in a deposit for 7 years. The matured amount was then invested in a scheme offering 10% Compound Interest compounded annually, thereby procuring an interest of Rs.1638 in 2 years. What was the original sum?
The loss incurred in a sale of an article is equal to 60% of the selling price of the article. What is the actual loss per cent?
The sum of the ages of a father and son is 45. Six years ago, their ages were in the ratio 10 : 1. How old will the son be after six years?
P, Q and R are the volumes of a cone, hemisphere and a cylinder with equal radius and height. What is the value of $$P : Q : R$$ ?