Question

Addison was a spectator at her town's air guitar competition. Contestants were allowed to play either he acoustic or electric air guitar, but not both. Addison recorded which type of guitar each contestant played. She also counted the number of contestants wearing different kinds of pants, as there were some interesting stylistic choices. Leather Velvet 7 4 Acoustic guitar Electric guitar 5 3 What is the probability that a randomly selected contestant played an electric guitar or was dressed in velvet? Simplify any fractions.

Answer 1

Leather Velvet Total

Acoustic 7 4 11

Electric 5 3 8

Total 12 7 19

We can define the following events:

A= contestant use electric guitar

B= the selected is velvet

And we want to find this probability:

P(A or B) = P(A) + P(B) -P(A and B)

P(A) = 8/19

P(B)= 7/19

P(A and B) = 3/19

And replacing we got:

P(A or B) = 8/19 + 7/19 - 3/19 = 12/19