During a 20% off sale, the sale price of a radio was $35.96. What was the regular price of the radio?

The last time i bought this product , it cost $20.00 but it looks like it cost 29. 60 today? what is the increase

Our goal is to collect email addresses from 60% of customers who purchase a product." so that means if i talk to 95 customers, i need to persuade to provide an email address?

Jackie purchased 3 bottles of water and 2 cups of coffee for a family for $7.35. brian bought 4 bottles of water and 1 cup of coffee for his family for $7.15. how much does each bottle of water cost? how much does each cup of coffee cost? i need this done