I need your help with this problem. Please help me by answering and showing explanations.

Problem 3. You set up a food truck which serves hamburgers and tacos, both for the bargain price of $1. In an average day, you sell 7 hamburgers and 432 tacos. (Your burgers aren't very good.) The standard deviation of the daily amounts sold are 5 hamburgers and 12 tacos. If your total revenue has a standard deviation of $13, what is the correlation coefficient for the daily numbers of hamburgers and tacos you sell