From the given price function, we have;
(a) [tex] \frac{dp}{dq} = - 13[/tex]
(b) The point elasticity of demand is 0.0256; inelastic demand
(c) $46.6
(d) Increase
a. The given function is presented as follows;
[tex]p = 50 \times (151 - q) ^{0.02 \times \sqrt{q + 19} } [/tex]
Differentiating the above function with a graphing calculator and setting q = 150 gives;
[tex] \frac{dp}{dq} = - 13[/tex]
b. The point elasticity of demand is given by the formula;
[tex] e \: = \frac{dq}{dp} \times \frac{p}{q} [/tex]
When q = 150, we have;
P = 50
Which gives;
[tex]e \: = \frac{1}{13} \times \frac{50}{150} = 0.0256[/tex]
The point elasticity of demand, E = 0.0256
c. If the quantity demanded decreases from 150 to 140 units, we have;
[tex]0.0256 \: = \frac{1}{13} \times \frac{p}{140} = [/tex]
Which gives;
p = 46.6
d. Given that increase in price, from 46.6 to 50, increases the quantity demanded from 140 to 150, therefore;
R = p × q
Learn more about elasticity of demand here;
https://brainly.com/question/19141990