The cost of painting the walls of a hall 30 meters long, 20 meters broad and 12 meters high, if it costs 25 paise per sq. metre

There is a rectangular field of length 60 m and width 20 m. A path of uniform width and area 516 sq m surrounds the field. Find the width of path

P, Q and S are moving on a circular stadium of circumference 2100 m. When P completes one round, Q is still 700 m behind. When S completes one round, Q is 300 m ahead of him. How far from the starting point three of them will meet for the first time?