An instructor has a test bank consisting of 300 easy True/False questions, 200 difficult True/False questions, 500 easy multiple choice questions (MCQ) and 400 difficult multiple choice questions. If a questions is selected at random from the test bank, what is the probability that it will be an easy question given that it is a multiple choice question.

Explanation

total no of question = 1400

`p(a) = (300+500)/1400 = 800/1400`

`p(b) = (500+400)/1400 = 900/1400`

`p(a nn b) = 500/1400`

`p(a|b) = (p(a nn b))/(p(b))`

`= (500/1400)/(900/1400)`

`= 5/9`

answer