Let's calculate the discount for each book and then the final price after the discount:

1. $25.00 book: 30% off because it's over $22.00
   Discount = 30/100 * $25.00 = $7.50
   Final price = $25.00 - $7.50 = $17.50

2. $18.00 book: 20% off because it's between $10.01 and $20.00
   Discount = 20/100 * $18.00 = $3.60
   Final price = $18.00 - $3.60 = $14.40

3. $21.00 book: 20% off because it's between $10.01 and $20.00
   Discount = 20/100 * $21.00 = $4.20
   Final price = $21.00 - $4.20 = $16.80

4. $35.00 book: 30% off because it's over $22.00
   Discount = 30/100 * $35.00 = $10.50
   Final price = $35.00 - $10.50 = $24.50

5. $12.00 book: 20% off because it's between $10.01 and $20.00
   Discount = 20/100 * $12.00 = $2.40
   Final price = $12.00 - $2.40 = $9.60

6. $10.00 book: 15% off because it's under $10.00
   Discount = 15/100 * $10.00 = $1.50
   Final price = $10.00 - $1.50 = $8.50

7. $8.50 book: 15% off because it's under $10.00
   Discount = 15/100 * $8.50 = $1.28
   Final price = $8.50 - $1.28 = $7.22

8. $23.00 book: 30% off because it's over $22.00
   Discount = 30/100 * $23.00 = $6.90
   Final price = $23.00 - $6.90 = $16.10

9. $6.00 book: 15% off because it's under $10.00
   Discount = 15/100 * $6.00 = $0.90
   Final price = $6.00 - $0.90 = $5.10

10. $15.50 book: 20% off because it's between $10.01 and $20.00
    Discount = 20/100 * $15.50 = $3.10
    Final price = $15.50 - $3.10 = $12.40

11. $30.00 book: 30% off because it's over $22.00
    Discount = 30/100 * $30.00 = $9.00
    Final price = $30.00 - $9.00 = $21.00

12. $9.50 book: 15% off because it's under $10.00
    Discount = 15/100 * $9.50 = $1.43
    Final price = $9.50 - $1.43 = $8.07

Now, let's add up all the final prices to find out how much Gordon will spend on books after applying the discounts:

$17.50 + $14.40 + $16.80 + $24.50 + $9.60 + $8.50 + $7.22 + $16.10 + $5.10 + $12.40 + $21.00 + $8.07 = $161.19

Gordon will spend $161.19 on books after applying the discounts.
각 책의 할인 금액과 할인 후 최종 가격을 계산해 보겠습니다:

1. $25.00 책: 22.00달러를 초과하므로 30% 할인
   할인 = 30/100 * $25.00 = $7.50
   최종 가격 = $25.00 - $7.50 = $17.50

2. $18.00 책: 10.01달러에서 20.00달러 사이이므로 20% 할인
   할인 = 20/100 * $18.00 = $3.60
   최종 가격 = $18.00 - $3.60 = $14.40

3. $21.00 책: 10.01달러에서 20.00달러 사이이므로 20% 할인
   할인 = 20/100 * $21.00 = $4.20
   최종 가격 = $21.00 - $4.20 = $16.80

4. $35.00 책: 22.00달러를 초과하므로 30% 할인
   할인 = 30/100 * $35.00 = $10.50
   최종 가격 = $35.00 - $10.50 = $24.50

5. $12.00 책: 10.01달러에서 20.00달러 사이이므로 20% 할인
   할인 = 20/100 * $12.00 = $2.40
   최종 가격 = $12.00 - $2.40 = $9.60

6. $10.00 책: 10.00달러 미만이기 때문에 15% 할인
   할인 = 15/100 * $10.00 = $1.50
   최종 가격 = $10.00 - $1.50 = $8.50

7. $8.50 책: 10.00달러 미만이기 때문에 15% 할인
   할인 = 15/100 * $8.50 = $1.28
   최종 가격 = $8.50 - $1.28 = $7.22

8. $23.00 책: 22.00달러를 초과하므로 30% 할인
   할인 = 30/100 * $23.00 = $6.90
   최종 가격 = $23.00 - $6.90 = $16.10

9. $6.00 책: 10.00달러 미만이기 때문에 15% 할인
   할인 = 15/100 * $6.00 = $0.90
   최종 가격 = $6.00 - $0.90 = $5.10

10. $15.50 책: 10.01달러에서 20.00달러 사이이므로 20% 할인
   할인 = 20/100 * $15.50 = $3.10
   최종 가격 = $15.50 - $3.10 = $12.40

11. $30.00 책: 22.00달러를 초과하므로 30% 할인
   할인 = 30/100 * $30.00 = $9.00
   최종 가격 = $30.00 - $9.00 = $21.00

12. $9.50 책: 10.00달러 미만이기 때문에 15% 할인
   할인 = 15/100 * $9.50 = $1.43
   최종 가격 = $9.50 - $1.43 = $8.07

이제 모든 최종 가격을 합산하여 할인을 적용한 후 Gordon이 책에 지출할 금액을 알아봅시다:

$17.50 + $14.40 + $16.80 + $24.50 + $9.60 + $8.50 + $7.22 + $16.10 + $5.10 + $12.40 + $21.00 + $8.07 = $161.19

고든은 할인을 적용한 후 책에 $161.19를 지출할 것입니다.