Questions on a pop quiz are worth 4 points for each multiple choice question, `m`, and 6 points for open-response question, `r`. Write an expression to determine the total number of points on the quiz in terms of `m` and`r`.
The total number of points on the quiz can be determined using the following expression:
Total points = (4 * m) + (6 * r)
where `m` represents the number of multiple choice questions and `r` represents the number of open-response questions.