Answer: (1) p = $110
(2) shotage of 25 milion phones
Step-by-step explanation:
(1) For the equilibrium, q supply = q sales
sales: q=-p+156
supply: q=4p-394
4p-394 = -p+156
4p + p = 156 + 394
5p = 550
p = 110
(2) p = 105
sales: q=-p+156
q = -105 + 156
q = 51
supply: q=4p-394
q = 4.105 - 394
q = 420 - 394
q = 26
As sales > supply, is is a shortage of 51 - 26 = 25 milion phones