Answer: 3.625 yards above the sea level.
Step-by-step explanation:
Given: The elevation of top of top of blue mountain above the sea level= [tex]19\frac{3}{4}=19.75\ yards[/tex]
The length of the lowest point below the sea level= 12.5 yards
The total elevation from the lowest point under the sea and the top of blue mountain=19.75+12.5=32.25 yards
The midpoint between the top and bottom of the slope = [tex]\frac{1}{2}\times32.25=16.125\ yards[/tex]
Since the ski lift is going to pick them up at the midpoint between top and bottom of the slope.
Therefore, the elevation at which they will be picked up= 19.75-16.125=3.625\ yards above the sea level.
