The following table represents the total cost, in dollars (y) to join a gym for x number of months.The cost includes a one time joining fee of $10 . Does the data in the table represent a proportional relationship or a non-proportional relationship? how do you know?

x 1 2 3 4 5
y 25 40 55 70 85

Question

The following table represents the total cost, in dollars (y) to join a gym for x number of months.The cost includes a one time joining fee of $10 . Does the data in the table represent a proportional relationship or a non-proportional relationship? how do you know?

x 1      2      3       4     5 
y 25   40    55     70    85

texaschic101 · Answer

make a proportion using the points and see if it is equal
1/25 = 2/40 --- cross multiply
(25)(2) = (1)(40)
50 = 40 -- no...this is not proportional..it does not equal

another example :
x  1,2,3,4
y  3,6,9,12

1/3 = 2/6 -- cross multiply
(3)(2) = (1)(6)
6 = 6 -- correct...this would be proportional