The mean of marks secured by 45 students in division A of class X is 56, 40 students of division B is 52 and that of 40 students of division C is 50. Find the mean of marks of the students of three divisions of Class X.
If price of an article decreases from Rs P1 to Rs 75, quantity demanded increases from 1000 units to 1200 units. If point elasticity of demand is 3.2 findmP1?