If quantity of good X demanded increases from 4000 units to 5000 units when price of good Y increases from Rs 75 to Rs 90, find Arc Cross elasticity of demand?
The mean of marks secured by 35 students in division A of class X is 65, 45 students of division B is 61 and that of 70 students of division C is 59. What is the mean of marks of the students of three divisions of Class X?