The demand function is:

q = 2000(90-p)^1/2

where p is the price in cents and q the number of riders per day.

The question is asking if you lower p does q go up or down.

Raising p by a small amount makes 90-p smaller so (90-p)^(1/2) is smaller and so q is smaller. Similarly reducing p make 90-p larger and hence q larger.

CB