There are two Investments A and B which contain 10 shares each. Investment A contains 6 IT shares and 4 Bank shares. Investment B contains 3 IT shares and 7 Bank shares. A draw of a share is made at random from one of the Investments. It is a Bank share. An educated guess may suggest that the drawing of the Bank share has been made from Investment A. Use the Bayes theorem to determine the posterior probability that the Bank share came from Investment A.