D is partly constant and partly varies with when V=40 D=15 and when v=54 D=192
D = mV + b
Using the two data points, you must solve
40m+b = 15
54m+b = 192
Once you have m and b, you can answer other questions.
Using the two data points, you must solve
40m+b = 15
54m+b = 192
Once you have m and b, you can answer other questions.