math
posted by amy on .
The expression 9a + 6s is the cost for a adults and s students to see a musical performance.
a. Find the total cost for three adults and five students.
b. The number of adults and students in a group both double. Does the cost double? Explain your answer using an example.
c. The number of students doubles, but the number of adults is cut in half. Is the cost the same? Explain your answer using an example

a. Substitute 3 for a and 5 for s and compute.
27 + 30 = ___?
b. Does 9*(2a) + 6*(2s) = 2*(9a + 6s) ?
The order that three numbers are multiplied does not affect the result.
c. Does 9*(2a) + 6*(s/2) = (9a + 6s) ?
Put another way, does
18a + 3s = 9a + 6s
Not unless 3a = s 
a. 105 for 5 students and 108 for 3 adulots

109