A bicycle wheel has diameter 70 cm. How many complete revolutions does it make while the bicycle travels 1.32 km? Take π = 22/7.

One revolution carries the bicycle forward by the wheel's circumference, πd = (22/7) × 70 = 220 cm. The journey is 1.32 km = 132000 cm, so the count = 132000/220 = 600. (Using the radius 35 cm in place of the diameter halves each revolution and wrongly doubles the count to 1200.)