will a 225-60-16 tire work on a car with 215-65 16 inch tire?

Yes it would, as long as the 225/60-16 tire has an equal, or greater than, load index and speed rating of the original equipment tire.

3 tires one size and one another? If they are the same height, it might be ok. I'm not going to do the math, i am not even sure what you are asking or why. Yes, tires work on cars, Yes, 16 inch tires fit on 16 inch wheels. A 215 is less than a half inch narrower than a 225, so of course the tire will fit on the rim.

This is an acceptable swap however it is not a perfect fit. The 225/60–16 is .37" smaller in overall diameter and is .40" wider. Your speedometer will read around 1 mph slow. Other than that this is an acceptable swap.

Yes it would. Size difference would be very little, so likely it won't rub. just make sure you have the same tire size for all 4 corners.

depends on the rim size(width)