What would the height need to be for this curve to be a density curve?1/8 or 1/12, 0r 1/20, or 1

Question

line starts from 8 to -----------------------------20

Answer 1

The width of the curve is 12, and the area must be 1 for the total probability to be =1. The figure is a rectangle with area equal to width*height. If 12*height = 1, the height must be 1/12.