On a certain principal, simple interest amounts to Rs. 2,000 in two years at the rate of 10% p.a. What will be the difference in the amount of interest if the same is compounded on annual basis?
5 hrs after a goods train passed a station, another train travelling at a speed of 70 km/hr following that goods train passed through that station. If after passing the station the train overtakes the goods train in 9 hours. What is the speed of the goods train?