Austin and Jenny are at the grand opening celebration of a supermarket. They each spin a wheel with10 equal-sized slices, as shown below. When the wheel is spun, the arrow stops on a slice at random. If the arrow stops on the border of two slices, the wheel is spun again.

(a)If the arrow stops on a black or white slice, then Austin wins a gift card. Find the odds against Austin winning a gift card.

(b)If the arrow stops on a grey or white slice, then Jenny wins a gift card. Find the odds in favor of Jenny winning a gift card.