If the lengths of the two parallel sides of a trapezium are 7 cm and 9 cm and its area is 80 cm2. Find the distance between its parallel sides (in cm).
A shopkeeper purchased a pen drive of marked price Rs. 1000 at successive discounts of 10% & 15% respectively. He spent Rs. 35 on packaging and sold it on Rs. 1000. Calculate the Gain percent.