If the value of x increases and the value of y also increases then we can say that the slope is Increases,
If the value of x increases but the value of y decreases then we can say that the slope is decreases.
In the given coordinates of tempreature and icecreams sold is
as the value of Tempreature increases from 60 to 80, the number of icecreams (value of y) is also increases,
but at tempreature =90 the number of icecreams is 20,
thus, the value of y is decreases at x=90
Hence slope changes sign
first it gets positive from tempreature (0 to 80) and then decreases to 90
Answer : C) Slope changes sign
