Please help me get this one correct please and thank you!

You are at a restaurant and owe $38 for your meal. you want to leave a 20% tip. how much will your tip be?

Choose the more precise measurement. 26.4 cm or 8.39 cm

The oates family went out for dinner the price of the meal was $33.95 the sales tax was 7.25% of the price of the meal . the tip was 15% of the meal and the sales tax . how much money did the oates family pay for the meal, including tax and tip