Choose the correct number to replace the incorrect from the alternatives given to keep the series in order.

3, 7, 13, 21, 33, 43, 57, 73 

If the side of a square is increased by 20% the area of the square is increased by

Two towers are 35 m and 50 m height and 20m apart on level ground. Find the length of the rope connecting their tops. 

A and B started a business investing Rs.22,500 and Rs.35,000 respectively. Out of a total profit of Rs.13,800 B's share is