The probability of selecting a blue or green ball on the first draw is 1/2
Probability is the likelihood or chance that an event will occur. It is expressed as:
Probability = Expected outcome/Total outcome
If a bag of the same size small balls contains 6 blue balls, 5 red balls, 5 yellow balls, and 4 green balls, the:
Total outcome = 6 + 5 + 5 + 4
Total outcome = 20 balls
Get the expected outcome
Pr(blue ball) = number of blue/Total outcome = 6/20
Pr(green ball) = number of green ball/Total outcome= 4/20
Probability of selecting a blue or green ball on the first draw = 6/20 + 4/20
Probability of selecting a blue or green ball on the first draw = 10/20 = 1/2
Hence the probability of selecting a blue or green ball on the first draw is 1/2