Micah downloads music from an online music store. He pays $1.00 for each song, but if he buys three songs he gets a fourth song for free. Does this relationship have a constant rate of change or a varying rate of change?

this relationship has a constant rate because the pattern will stay as buy three get the 4th one free

Step-by-step explanation:

A varying rate of change.

Step-by-step explanation:

He will have spend 1 dollar for one song, making that point (1,1), 2 dollars for two songs (2,2), 3 dollars for 3 songs (3,3), but when he buys a fourth song, which is free, he has still only spent 3 dollars, making the point (4, 3).

(That's with the amount of songs as the x value and money spent as the y-value)