A new shoe comes in two colors, black or red, and in sizes from 5 to 12, including half sizes. If a pair of the shoes chosen at random for a store display, what is the probability it will be red and size 9 or larger?

Answer 1

So it could be sizes: 9, 9.5, 10, 10.5, 11, 11.5 or 12

let's pick one of the sizes, say size 10
prob (red, and size 10) = (1/2)(1/14) , (there are 14 possible sizes)
but the same probability is true for any of the 7 required sizes

prob(your event) = 7(1/2)(1/14) = 1/4