The first one I need help with that one

Answer:
5% Sales tax is $3.375 and total amount is $70.875. I don't know if they want u to simplify or not so I'll leave the answer this way just incase.
Step-by-step explanation:
You do cross multiplication.
1. ?/67.50 = 5/100
2. then you cross multiply 67.50 x 5 = 337.5
3. Divide 337.5 by 100 = 3.375