Two sums are in the ratio 4:3. Both the sums are lent at 5% per annum and 10% per annum under compound interest for two years. The difference between the interest at the end of two years is Rs. 1540. What was the sum lent at 10% per annum?

In a factory, the salary of each worker is increased in the ratio 22 : 25 but the number of workers is decreased by $$ 26{2\over3}\% $$. The net effect on the salary is: 

If cos²α + cos²β = 2, then the value of tan³ α + sin⁵ β is :

A moving train crosses a man standing on a platform and a bridge 640 metres long in 15 seconds and 35 seconds respectively. What will be the time taken by the train to cross a platform 1280 meters long?

In a business A and B gained some amount in a certain ratio. B and C received the profit in the ratio as that of A and B. If A received ₹ 6,400 and C received ₹ 10,000. Find the share of B 

The average of 21 consecutive natural numbers is 53. What is the value of the smallest of these 21 numbers?