If the gaming system was $250 and was discounted by 25%. 25% of 250 would be 62.5. The price dropped to $62.50 but since a customer had opened it, it dropped by other 10% making it only $6.25.
Therefore you're expected to win 1 ticket out of every 5 you purchase. So if you purchase 50 you can expect to win 10 tickets. Therefore the answer is C.