A 7 to 3 ratio means that for every time they sell 7 burgers with cheese sold, they also sold 3 burgers without cheese.
So you solve this by figuring out how many times they sold 7 burgers and then you use that number to find your answer.
35 / 7 = 5
So they sold 7 burgers 5 times.
So that means that they also sold 3 burgers 5 times since for every 7 burgers with cheese they sell 3 burgers without cheese.
So 3 * 5 = 15
You then add your two numbers and you have your answer.
35 burgers with cheese + 15 burgers without cheese = 50 burgers total.
