this question is the 2nd question in the 2019 October sat math no calculator section, I am confused arent we meant to multiply?

You are a clerk at convenience store. a customer owes 11.69 for a bag of potatoes chips. she gives you a five dollar bill. how much change should the customer receive?

Ben is three times as old as samantha, who is two years older than half of michel's age. if michel is 12. how old is ben?

Solve with work adding cheese to a mcdonalds quarter pounder increases the fat content from 21g to 30g. what is the percent of change ?