Dogs are inbred for such desirable characteristics as color; but an unfortunate by-product of such inbreeding can be the emergence of characteristics such as deafness. a 1992 study of bull terriers (by strain and others, as reported in the veterinary journal) found the following:

(i)
50% of the studied bull terriers are white.

(ii)
11% of the studied bull terriers are deaf.

(iii)
20%

of the white bull terriers are deaf.
what is the probability that a randomly chosen bull terrier is white and deaf?

.11 / .50 = .22

.20 / .50 = .4

.11 / .20 = .55

.50 * .11 = .055

.50 * .20 = .1

.11 * .20 = .022