Question

How do I do this question

The rear wheel of Emma’s bicycle has a diameter of 65cm. She cycles 3.2km to school each morning. How many complete revolutions will her wheel do during the journey

Answer 1

we know that
circumference=2*pi*r
for r=65/2----> r=32.5 cm
circumference=2*pi*32.5-----> 204.1 cm
so
one revolution of Emma’s bicycle is equal to 204.1 cm-----> 2.041 m
3.2 km-------> 3200 m
1 revolution---------> 2.041 m
x rev------------> 3200 m
x=3200/2.041 ----> x=1567.86 revolutions

the answer is
1567 complete revolutions