Last question i'm on

Marla bought a book for $12.95, a binder for $3.49, and a backpack for $44.99. the sales tax rate is 6%. find the amount of tax and the total she paid for these items

The bottom of a slide at the playground is 6 feet from the base of the play set. the length of the slide is 10 feet. how tall is the slide. 11.66 feet 10 feet 6 feet 8 feet

Ineed with question three. i don't understand how i'm supposed to achieve 3 marks.