In: Economics
The inverse demand function of specific commodity is given by ??(??) = ?20?? + 1400, where ?? and ?? are the price and quantity of the commodity, respectively.
a- Determine the maximum consumption.
b- If the price is $500 per unit, calculate consumption, consumers’ gross surplus, consumers’ net surplus, and the revenue collected by the producers.
c- If the price increases 40%, calculate change in demand and lost surplus for the consumers.
d- What is the consumers’ elasticity? Is it elastic or inelastic?
e- If the price rises by 3%, the quantity demanded falls by 1.5%.
f- If the elasticity of demand for a commodity were estimated to be 1.5, then a decrease in price from $2.0 to $1.90 would be expected to increase daily sales by how much?
The inverse demand is given as
.
(a) The maximum consumption will be where Q is large enough to
be just feasible. For P=0, we have
or
. Hence, at zero price, quantity consumed will be 70. The
consumption can not be more than this quantity, as negative price
is not feasible.
(b) At P = $500, we have the demand as
or
.
Area of region ABOFEA can be divided into area of triangle ABE
and area of rectangle BOFE. Area of triangle ABE will be
or
or
dollars. Area of rectangle BOFE will be
or
or
dollars.
The gross consumer surplus will be the area of ABOFEA, which is $20250 plus $22500 or $42750. The net consumer surplus, which is gross CS minus the total expenditure on those 45 units will be the area of triangle ABE, which is $20250. The revenue collected by producers will be price times quantity, ie the area of rectangle BOFE, which is $22500.
(c) If price increases by 40%, then price will be
dollars. For $700, the demand would be
or
. Change in demand is (-)10 units.
Current net surplus will be
or
dollars. The current expenditure or producer's revenue is
or
dollars. The current gross revenue is hence $36750. Hence,
decrease in gross CS is $6000, and decrease in net
CS is $8000.
(d) The price elasticity is the ratio of percentage change in
quantity and percentage change in price. The price elasticity of
demand is
or
. The inverse demand was
, and hence the demand function will be
. The ealsticity is hence
or
or
.
Checking for both points, we have at first ($500),
, and at later on (P=$700),
. Hence, the demand curve is said to be inelastic above price
equal $700, while elastic below $700, and unitary elastic at
$700.
(e) If price rises by 3% and quantity of demand falls by 1.5%,
the elasticity would be
. Equating it to the founded elasticity formula
, we have
or
or
. Putting in the demand function
, we have
or
or
, and hence
. Hence, the incresae in P of 3% and decrease in Q of 1.5% occurs
at where the price is $466.66 and quantity is 46.66.
(f) If the elasticity of demand for a commodity be
, ie
. A decrease in price from $2.0 to $1.90 would mean that the price
decreased by
or
or
,
ie 5%. Hence, as
, hence
or
, ie demand would decrease by 7.5 percent.