Two trains of equal length take 10 seconds and 15 seconds respectively to cross a telegraph post. If the length of each train be 120 meters, in what time (in seconds) will they cross each other traveling in opposite direction? 

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?

Two people, Savita and Karan, get their sales commissions based on the number of items sold each month. Their total sales commission amounts to Rs. 56,100 in a particular month. If savita got her commission 12 % higher than Karan, how much commission did Karan earn? 

If 4 litres of water is evaporated on boiling from 12 litres of salt solution containing 7 percentage salt, the percentage of salt in the remaining solution is 

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?