40 ÷ 0.80 ÷ 0.25 = ?

45% of √225 + 21 = ?

6085 − 4017 + 1496 − 1124 = ?

If the diameter of a cylinder is 20 cm and its height is 20 cm, then the surface area (in cm²) is

A contractor agreeing to finish a work in 150 days employed 75 men, each working for 8 h daily. After 90 days only 2/7 of the work was completed. How many more men would be put on now, each working 10 h daily so as to finish the work in the stipulated time?

A retailer buys 30 pens from a wholesaler and pays equal to marked price of 27 pens. If he sells the pens at the marked price, his profit per cent in the transaction is

A horse worth Rs. 9000 is sold by A to B at a loss of 10%. B sells the horse back to A at 10% gain. The result is

Ten years ago A was half of B in age. If the ratio of their present ages is 3 : 4, what will be the total of their present ages?

The banks of a river are parallel. A swimmer starts from a point on one of the banks and swims in a straight line inclined to the bank at 45° and reaches the opposite bank which is 20 m from the starting point. The breadth of the river is