Answer:
Step-by-step explanation:
A. It costs $20 per adult. If this is a cost fuction, which it is because the wording is "the cost (in dollars) for a adults and c students", adult is a, the cost for 1 adult, 1a, is 20. That relates the number of adults to the cost of 1 adult.
It costs $13 per student. Again, this is a cost function, so since student is c, the cost for 1 student, 1c, is 13. That relates the number of students to the cost of 1 student.
B. The total cost for 4 adult and 24 students looks like this:
20(4) + 13(24) which is 80 + 312 = $392
C. If you have 3 adults and 3 students in your group, the cost is 20(3) + 13(3) which is $99. If you double the number of each, let's see if the cost doubles. We will "up" the numbers to 6 each. 20(6) + 13(6) = $198. Is $198 the double of $99. Yes it is. Let's do it again to check. Let's double the 6.
20(12) + 13(12) = $396, and $198 doubled does in fact equal $396. So there you go!
