A circular rim 28 inches in diameter rotates the same number

Understanding the question:
Note that the question talks about 2 different metrics:
1) revolution per second which gives the number of revolution made in a second
2) inches per second - which is the distance travelled per second.
It is important to understand these 2 metrics and how they are related.

Facts to refer:
We know that: Distance travelled = Number of revolutions * Circumference of the circle
Extending that slightly to become rates: Distance travelled per second = Number of revolutions per second * Circumference of the circle.

What's given in the question:
Inches per second ie., distance per second is equal for 28 inch and 33 inch circles.
Number of revolutions per second by 28 inch = x

What is asked for:
Number of revolutions per minute by 35 inch = ? Lets have this as variable a. Question asks this in terms of x, so there is no need to solve for x.

Solution:
Note that 28 inch is in seconds. Since we need the answer in minutes, lets convert that:
Number of revolutions per second by 28 inch = x*60
Applying the earlier stated formula: Distance travelled per second = Number of revolutions per second * Circumference of the circle, we have:
x*60*28*pi=a*35*pi
Solving this equation yields a= 48x.