10. If 90% of a number y is 10, what is y? 11. What is the initial investment if $105 is its 110%? 12. What is the initial investment if $12500 is its 95%? 13. If a $15 item is discounted $6, what is the discount percentage? 14. Lee buys a cup of coffee at the price of $4.10 before tax. Assuming that the sale tax is 10%, and Lee gives a 15% tip. What is the total price of her coffee? 15. Lee does not remember the original price of her new backpack, but she remembers that she has a discount at 35%, and her total payment is $75. Assuming that the sale tax is 10%. What is the original price of Lee's new backpack? a