The average height of 30 boys out of a class of 50 is 160 cm. If the average height of the remaining boys is 165 cm, the average height of the whole class (in cm) is:
Two trains start from a certain place on two parallel tracks in the same direction. The speed of the trains are 45 Km/hr and 40 Km/hr respectively. The distance between the two trains after 45 minutes will be