Let D be partly constant and partly vary with V. When V = 40, D = 150 and when V = 54, D = 192.
To find the formula connecting D and V, we can use the two given points to determine the slope (a) and the y-intercept (b) of the equation:
D = aV + b
We can start by finding the slope or the rate of change of D with respect to V:
a = (Dβ - Dβ)/(Vβ - Vβ)
a = (192 - 150)/(54 - 40)
a = 42/14
a = 3
Next, we can use one of the points to substitute for D, V, and a to solve for b:
150 = 3(40) + b
150 = 120 + b
b = 150 - 120
b = 30
Therefore, the formula connecting D and V is:
D = 3V + 30.