What is the compound interest (in ₹) on ₹80,000 for 3 years when the rate of interest is 5%, 8% and 10% per annum for the 3 successive years, the interest being compounded annually?
A student takes 1.25 hours to travel from home to school at a speed of 4 km/h. By what percentage should he increase his speed to reduce the time by 25% to cover the same distance from school to home?
Pipes A and B together can fill an empty tank in 30 hours, whereas pipes B and C together can fill it in 24 hours. A, B and C together can fill the tank in 20 hours. In how many hours can pipe B alone fill 35% of the tank?