Darya is a real estate broker with a house listing. Darya estimates that this listing will cost her $2400 for various expenses. If Darya sells the house within 6 months, she will receive a commission of $20,000. If she does not sell the house within 6 months, the listing will expire, and she will not receive a commission, but she still must pay the $2400 for various expenses. Darya estimates the probability that she sells the house within 6 months is 80%. Determine Darya’s expectation for this listing.