Introduction to probability

Can you give me the answer for this question, so I can compare it to mine.

Exercise 6.6.

Skittles. Chris has 32 Skittles candies. Nine are red, three are blue, seven are yellow, five are orange, and eight are purple. Exactly four are sour, and all of these sour Skittles are purple. Chris picks one Skittle at random. a. What is the probability he selected a red or blue one? b. What is the probability he selected a sour one? c. Given that he selected one that is not sour, what is the probability it was purple?

These next two exercises, please solve and explain.

Exercise 6.7.

Homework. Joe works on homework 25% of the time. He is on the computer 40% of the time. He likes to do homework on the computer, so 30% of the time that he is on the computer is spent doing homework. What is the probability that he is on his computer, given that he is doing his homework?

Exercise 6.8.

Depression and anxiety. According to the National Institute of Mental Health (from www.nimh.nih.gov/statistics/1ANYANX_ADULT. shtml), in any year, 18.1% of all U.S. adults suffer from anxiety disorders. Among people who have anxiety disorders, 30.2% are between 18 and 29 years old. According to the 2010 U.S. Census, approximately 10% of the U.S. adults are between 18 and 29 years old. a. Calculate the chance that a randomly selected 18-29 year old American has an anxiety disorder. b. Calculate the chance that a randomly selected American is 18-29 years old AND has an anxiety disorder.

Ward, Mark; Gundlach, Ellen. Introduction to Probability (p. 76). W. H. Freeman. Kindle Edition.