A bicycle wheel covers 11kilometre in 2500 revolutions. What is the radius of the wheel in centimetres. Whith Formula

11 km = 11,000 m

circumference of wheel = 11000/2500 = 4.4 m = 440 cm

2π r = 440
r = 220/π = 70.03 cm

the radius is appr 70 cm