Solve problems involving discounts, including calculating the percentage discount

1. Come fly with me1: Determine which airfare is better value
2. Frankly financial: Determine which price is better value
3. Golden fleece: Calculate percentage discount
4. Carving up the blue: Calculate percentage discount
5. Screen saver: Calculate percentage discount
6. Ring appeal: Calculate a percentage discount
7. Fine leathers make fine birds: Calculate percentage discount
8. Rock on: Calculate a discount as a percentage
9. Detective Duck: Calculate a percentage reduction
10. Detective Duck: Write one number as a percentage of another
11. Detective Duck: 20%
12. Detective Duck: 25 000 reduced to 20 000... % discount.