A spinner with 8 equally sized slices has 2 yellow slices, 3 blue slices, and 3 red slices. The dial is spun and stops on a slice at random. What is the probability that the dial stops on a yellow or blue slice?

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )