r = 35 cm = \( \Large \frac{35}{100000}km \)

Now the distance covered in 1 revolution = \( \Large 2 \times \pi \times r \)

= \( \Large 2 \times \frac{22}{7} \times \frac{35}{100000} = \frac{220}{10000}\) = \( \large \frac{22}{100000}km \)

In 500 revolutions,

Distance covered = \( \Large 500 \times \frac{22}{10000} km \)

= \( \Large \frac{22}{20}km \) = \( \frac{11}{10}km \)

So \( \Large \frac{11}{10}\) km is covered in 1 minute.

60 min = 1 hr, distance covered

=\( \Large \frac{60 \times 11}{10}km \)

= 66 km

Hence, speed = distance/time

= 66km / 1 hr = 66 Km/hr