How do yo do this question I have to Solve the System by Substitution:

y = x-2
x + y = 4

Atown recently dismissed 5 employees in order to meet their new budget reductions. the town had 5 employees over 50 years of age and 19 under 50. if the dismissed employees were selected at random, what is the probability that exactly 2 employees were over 50? express your answer as a fraction or a decimal number rounded to four decimal places.