Question

An ordered list of 4 numbers is called a quadruple. A quadruple (p, q, r, s) of integers with p,q,r,s ≥ 0 is chosen at random such that 2p+q+r+s = 4. What is the probability that p+q+r+s = 3?

Answer 1

not clear, you mean what the probability 2p+q+r+s=4?

Answer 2

=3