Answer:
The cost of the stores will be the same when "-6" pair of shoes are bought, therefore they will never be the same in real world applications.
Step-by-step explanation:
In order to solve this problem we will create equations for each store, where "s" is the total number of shoe pairs that were bought.
For the store A:
total cost = 1100 + 66*(s - 11)
total cost = 1100 + 66*s -726
total cost = 374 + 66*s
For the store B:
total cost = 825 + 825*0.06*(s-11)
total cost = 825 + 49.5(s -11)
total cost = 825 + 49.5*s -544.5
total cost = 49.5*s +280.5
In order for the cost to be the same, the expressions must be equal, therefore:
374 + 66*s = 49.5*s +280.5
66*s - 49.5*s = 280.5 - 374
15.5*s = -93.5
s = -6.03
Since the value for pair of shoes is negative, this means that the cost for each vendors will never be the same.