If f is chosen at random from the set {2, 3, 4} and m is chosen at random from the set {9, 10, 11}, what is the probability that f is a factor of m?

U={2, 3, 4}x{9, 10, 11} 

and n(U)=9 


from which E = {(2,10), (3,9)} 


and so n(E)=2 

p=n(E)/n(U)=2/9