Answer
See below.
Work Step by Step
The midpoint $M$ of the line segment from $P_1(x_1,y_1)$ to $P_2(x_2,y_2)$ is: $(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2})$.
Hence:
$M=(\frac{33+99}{2},\frac{30+60}{2})=(66,45)$.
This means that at a depth of $66$ the pressure will be $45$.
