A function that increases proportionally to its current value. The larger the function gets, the faster it increases.

Which number produces a rationale number when multiplied by 1/5

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?

What are the values of each variable in the diagram below?