‘n Firma klassifiseer klante op twee maniere, volgens: / A firm classifies its customers in two ways according to:

(I) of die rekening agterstallig is en / whether the account is overdue and

(II) of die rekening nuut is (minder as twaalf maande) of oud. / whether the account is new (less than twelve months) or old.

‘n Analise van die firma se records verskaf ons van die volgende tabel van gesamentlike waarskynlikhede: / An analysis of the firm’s records provides the following table of joint probabilities:

Een rekening word ewekansig geselekteer. / One account is randomly selected.

Indien die rekening agterstallig is, wat is die waarskynlikheid dat dit ‘n nuwe rekening is? / If the account is overdue, what is the probability that it is new?