A The price elasticity of demand for imported whiskey is es
A - The price elasticity of demand for imported whiskey is estimated to be ?0.20 over a wide interval of prices. The federal government decides to raise the import tariff on foreign whiskey, causing its price to rise by 30 percent.
1 - Will the quantity demanded on imported whiskey rise or fall, and by what percentage amount?
2 - What is the percentage change in the total revenue after the tariff increases?
B - The XYZ Company developed the following quarterly sales forecasting model:
Yt = 6.32 + 0.01t
where Yt = predicted sales ($ million) in quarter t; t = 1 (First quarter of 2008), 2 (Second quarter of 2008), 3 (Third quarter of 2008), and so on.
3 - Given the time-series model, what is the period t for the fourth quarter of 2018?
4 - How much is the predicted sales for the fourth quarter of 2018?
Solution
Solution: Price elasticity of demand, ed = -0.20
A. 1) Since, ed is negative, this means there exists inverse relation between price and quantity demanded. So, the 30% increase in price will cause quantity demanded to fall.
ed = percentage change in quantitydemanded/percentage change in price
-0.2 = percentage change in quantity demanded/30
Thus, percentage change in qty demanded = -0.2*30 = -6. So, qty demanded will fall by 6%.
2)Total revenue = price*quantity. Say initially price, P= $y, and qty demanded, Q =x unit
After price change, P\' = y(1 + 0.3) = 1.3y
and, Q\' = x(1 - 0.06) = 0.94x
So, TR = xy and TR\' = (1.3y)*(0.94x) = 1.222xy
TR\' = (1 + 0.222)xy = (1+0.222)TR (Extra Note: Since, 1.222 > 1, there has been an increase in the total revenue)
So, percentage change in total revenue = 22.2%
B. 3) First quarter of 2008 implies t = 1
We have to find value of t, for fourth quarter of 2018.
Given the time-series, every fourth quarter of an year gives value of \'t\' as a multiple of 4.
Then, fourth quarter of 2008 gives t = 4
fourth quarter of 2009 gives t = 8 (=4*2) and so on.
Following this pattern, we get an arithmetic progression series: 4, 8, 12, ....
If 1st term is for 2008, 2nd for 2009, 3rd for 2010, and so on, then what term is for year 2018? Say it is \'n\'
So, n = (2018 - (2008 + 1)) = 11
We have to find 11th term of the series 4, 8, 12....., Here first term = a =4, common difference = d =8-4 = 4
Formula for nth term = a + (n - 1)*d
So, 11th term = 4 + (11 - 1)*4 = 44. So t = 44
4) Yt = 6.32 + 0.01t
For t = 44, Yt = 6.32 + 0.01*44 = 6.76
So, predicted sales for the fourth quarter of 2018 = $6.76 million.

