For the following questions answer them individually
Two trains 100 m and 120 m in length are moving in opposite direction, with speeds 18 m/s and 15 m/s respectively. In what time will they cross each other?
A certain principal amounts to Rs.15000 in 2.5 years and to Rs.16500 in 4 years at the same rate of interest. Find the rate of interest.
The list price of an article at a show room is Rs.2000, and it is being sold at successive discounts of 20% and 10%. Find its net selling price.