A student is selling tickets for the school's annual drama production. The price of a ticket is

denoted by the random variable X. Tickets sell for either $10 or $20. The probability that a ticket sells for $10 is

and the probability that it sells for $20 is 1 .

(1)

If the average (expected) price is known to be $16 determine the probability that a ticket

costs $20.

(2)

If the average price is not known but a random sample of 9 ticket sales is as follows:

$20, $10, $10, $20, $20, $20, $10, $10, $20. Using these data find an expression for the

likelihood function L().