Andrew randomly selects a number from 1-15. What is the probability that the number he selects is an even number?

I’m stuck on this i don’t understand.

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

The width of a rectangle is 20 units. can the perimeter p of the rectangle be 64 units when its length x is 11 units? no, because p = 2x + 2(20) no, because p ≠ 2x + 2(20) yes, because p ≠ 2x + 2(20) yes, because p = 2x + 2(20)