For the following questions answer them individually
If price of an article decreases from Rs 800 to Rs 750, when quantity demanded increases from Q1 units to 2250 units, and if point elasticity of demand is -2 find Q1?
Find the power of a convex lens if the image formed is at a distance of 20 cm from the lens when the object is placed on the other side of the lens at 60 cm from the optical centre?