The pedal cranks of a bike are 175mm long and the rear wheel makes 3 turns for each turn of the pedals. If the rear wheel is 700mm in diameter then calculate:

a) the number of turns made by the cranks while the bike is traveling 1km.

i did it this way: 700mm/2= R350mm 2x3.14x350mm=2198mm 2198/1000=2.198m

2.198m x3=6.594m 6.594m/1000m=151.6 the book says 152 rounded up i assume.

b) the average speed of rotation of the pedals in m/s if the kilometer is covered in 2 min 30 seconds.

this is the one i need help with please,