A sample space contains seven simple events: E1, E2, , E7. Suppose that E1, E2, , E6 all have the same probability, but E7 is four times as likely as the others. Find the probability of the given event. B = E2, E3, E6, E7

A sample space contains seven simple events: ,, , ..., 5. Suppose that ,, ,, ..., , all have the same probability, but , is four times as likely as the others. Find the probability of the given event, B= {E, Ea, Egs E,}