Question

What is the maximum number of times two planes can intersect? What is the minimum number of times they can intersect?

Answer 1

The minimum number of times two planes can intersect is zero, because if the planes are parallel to each other, they will never intersect. we can take the example of floor and roof, both are parallel to each other and no intersection. If the two planes are in same plane the maximum number of times they can intersect is infinite for example if we consider a line we can intersect at infinite points.