A bag contains x marbles. Half of the marbles are blue. Four less than the number of blue marbles are red. The remaining marbles are purple. What is the probability of choosing a purple marble at random?

Question

a. 2
b. 4
c. 1/2-(x/2-4)/x
d. x/2-4
e. x/2

please answer and explain

Answer 1

blue: x/2
red blue-4 = x/2-4
purple: 4

P(purple) = 4/x
crudely put, (c)