Reader's Digest Ran a Sweepstakes in Which Prizes Were Listed

Essay

Reader's Digest ran a sweepstakes in which prizes were listed along with chances of
winning: $1,000,000 (1 chance in 90,000,000), $100,000 (1 chance in 110,000,000),
$25,000 (1 chance in 110,000,000), $5,000 (1 chance in 36,667,000), and $2,500 (1 chance
in 27,500,000). Assuming that there is no cost of entering the sweepstakes, find the expected
value of the amount won for one entry. If the cost of entering the sweepstakes is the cost of
a postage stamp, is it worth entering the contest?