John has an account balance of $20. He receives his weekly paycheck for work at his part-time job in the amount of $110. He can’t find a bike he wants, so he buys some comic books for $40. Then John finds his dream bike priced at $80, as shown. If he buys the bike now, what will his account balance be?

Period is the time it takes for one “cycle” to complete. in the parent sine function, period is 2*pi since sin(0) = 0, sin(pi/2) = 1, sin(pi) = 0, sin(3pi/2) = -1, and sin(2pi) = 0. at that point, the sequence repeats itself. i’m not sure if your graph is similar to the sine function since you didn’t provide a picture, but you can find the period by looking at a graph.