7. A drawer contains four red socks and five blue socks.

(a) Three socks are drawn one at a time and then put back before the next

selection. Determine the probability that

(i) exactly two red socks are selected

(ii) at least two red socks are selected

(b) Repeat part (a) without replacement

answeres... ia) 80over243 ib) 304over729

iia) 5over14 iib) 17over42

(over is a fraction)