Two distinct numbers are selected simultaneously and at random from the set (1, 2, 3, 4, 5, 6). What is the probability that the smaller one divides the larger one? Express your answer as a common fraction.
1 will divide any so that is 5 pairs
2 divides 4 and 6 so there is 2 pairs
3 divides 6 so that is 1 pair
so 8 pairs are favourable
there are 6C2 = 15 pairs altogether
so P(little one divides the larger one) is 8/15