marbles = {"red": 5, "blue": 3, "green": 2}
total = sum(marbles.values())

for color, count in marbles.items():
    probability = count / total
    print(f"P({color}) = {count}/{total} = {probability}")

p_not_red = 1 - marbles["red"] / total
print(f"P(not red) = {p_not_red}")

# Output:
# P(red) = 5/10 = 0.5
# P(blue) = 3/10 = 0.3
# P(green) = 2/10 = 0.2
# P(not red) = 0.5