Expected Value Question.

Dear John, How are you ? I hope you are doing well, Could you help me regarding the following question please, Q: Carson products sell sweatshirts and is preparing for a World Cup Soccer match. The cost per sweatshirt varies with the quantity purchased as follows. Quantity Unit Cost ----------- ----------- 4000 $14 5000 $13.50 6000 $13 7000 $12.50 Carson must purchase the sweatshirts one month before the game and has analyzed the market and estimated sales levels as follows Unit Sales 4000 5000 6000 7000 Probability %15 %20 %35 %30 The estimated selling price is $25 for sales made before and during game day. Any sweatshirts remaining after game day can be sold at wholesale to a local discount store for $110. The expected profit if Carson purchased 6000 shirts is A. $64,500 B. $66,000 C. $69,000 D. $72,000 My answer is as follow first of all I have calculated the total expected unit sales as follow, =4000 unit * 15% + 5000 unit * 20% + 6000 units * 35% + 7000 units * 30% = 5800 Units. Sales at normal price 5800 units * $25 $145,000 Sales at discounted price 200 Units * $10 2000 Cost of sales 6000 units * $13 (78,000) -------------- The total expected profit $69,000 But the correct answer is as follow The total expected profit $ 64,500 According to the textbook. Could you tell me what is wrong in my answer?