From the question Radius of wheel = r = \[35\] cm
We know that one revolution of the wheel is equal to Circumference of the wheel
i.e., \[2\pi r\]
= \[2\times (22/7)\times 35\]
= \[220\] cm
But, from the question it is given that,
Speed of the wheel is \[66\] km/hr
= \[(66\times 1000\times 100)/60\] cm/min
= \[110000\] cm/min
∴ Number of revolutions in one min = \[110000/220=500\]
Therefore, \[500\] revolutions per minute should be made by the wheel make so as to keep a speed of \[66\] km/h