Question

D IS PARTLY CONSTANT AND PARTLY VARIES WITH V where V =40 d=150 and when V=54 D=192

Answer 1

d = mv+b

use the two data points to solve for m and b:
40m+b=150
54m+b=192
so, clearly, 14m=42, so m=3
Now find b and you can answer any questions about this equation.