The sum of all cars will be = 70 + 30 + 50 + 80 + 20 = 250
So,
the probability that’s the nexts car to drive by will be red = (red cars)/(total cars)
= 50 / 250 = 0.2
the probability that’s the nexts car to drive by will be blue = (blue cars)/(total cars) = 70 / 250 = 0.28
then
the probability that’s the nexts car to drive by will be red or blue
= 0.2 + 0.28 = 0.48
