There are 5 red tiles and 5 blue tiles with the letter A in a bag. There are also 6 red tiles and 4 blue tiles with the letter B in the bag. What is the probability that a randomly selected tile is blue or has the letter B?

Answer 1

p(Blue or B) = p(Blue) + p(B) – p(Blue and B).
= 9/(20)+ 9/20 - 4/20=14/20=.7

Answer 2

Probability of blue tile= 9/20
probability of letter b tile= 10/20= 1/2
Probability of blue or letter b= Probability of blue + probability of letter b
= 9/20 + 1/2
= 19/20