Final answer:
The expected value of the incentive for one customer is $53.33. If 90 customers choose a key and buy new cars, the dealership can expect to give up $4800 in sales.
Step-by-step explanation:
A) The expected value of the incentive for one customer who chooses a key and buys a new car can be calculated by multiplying the probability of winning ($1000 off) by the cost of winning (4 out of 75 keys). The probability of winning is 4/75, and the cost of winning is $1000.
Expected value = (Probability of winning) x (Cost of winning) = (4/75) x $1000 = $53.33
Therefore, the expected value of the incentive for one customer is $53.33.
B) If 90 customers come in and choose a key and all of them buy new cars, the dealership can expect to give up (90 x $53.33) = $4800 in sales.