Peggy Sue decided to enter her famous “Five-Alarm Chili” at her local chili-cooking contest.

Question

Peggy Sue decided to enter her famous “Five-Alarm Chili” at her local chili-cooking contest. Normally, she needs five tomatoes to make enough chili for her family of seven. How many tomatoes should she expect to use to make her famous recipe for 100 people?

Answer 1

Sounds like a call for proportions! Let's set up ratios of the form "tomatoes:Tomatoes::people::People".

 

5:x::7:100

 

"Cross-multiplying", we get 7x=500, which we can solve by dividing by 7. This doesn't come out evenly, because 500/7=71.42857.... To have enough tomatoes, we should round up, and call it 72 tomatoes, or 6 dozen!