Answer:
-0.10
Explanation:
To calculate this, we us the formula for calculating elasticity of demand (E) relevant for the demand equation as follow:
E = (P / Q) * (dQ / dP) .............................. (1)
Where,
Q = 30
P = 90
E = -0.3
dQ / dP = b = ?
We then substitute all the value into equation (1) and have:
-0.3 = (90 / 30) * b
-0.3 = 3 * b
b = -0.3 /3
b = -0.10
Therefore, appropriate value for the price coefficient (b) in a linear demand function Q is -0.10.
NB:
Although this not part of the question, but note that how the linear demand function will look can be obtained by first solving for the constant term (a) as follows:
Q = a - 0.10P
Substituting for Q and P, we can solve for a as follows:
30 = a – (0.1 * 90)
30 = a – 9
a = 30 + 9 = 39
Therefore, the linear demand equation can be stated as follows:
Q = 39 – 0.1P
