An express train is running between two stations with a uniform speed. If the diameter of each wheel of the train is 42 cm and each wheel makes 1200 revolutions per minute, find the speed of the train.

The minute hand of a clock is 8 cm long. Find the area swept by the minute hand between 8.30 a.m. and 9.05 a.m.

The base of a right triangle is 8 cm and its hypotenuse is 10 cm; the area of triangle is:

1. 24 cm²

2. 40 cm²

3. 48 cm²

4. 80 cm²