Sally and mabel had the same number of cards at first. after sally sold 18 of her cards, mabel had four times as many cards as sally. how many cardsdid each girl have at first?

If Sally sold 18 cards leaving Mabel with 4 times as many you would get the answer by multiplying 18 by 4 getting the answer 72.

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.