Question

An ongoing promotion at a department store gives customers 20 percent off the portion of their bill that is over $100. Ruby's total bill at the department store after the promotion has been applied is $250. If x represents the amount of money Ruby would have spent on the same purchase at the department store without the promotion, which of the following equations best models the situation?

Answer 1

We know that a department store gives 20 % off the portion of the bill that is over 100 dollars. 

Total bill is 250 and x is the amount of money she would have spent without the promotion.

The cost to which the discount applies is 0.8 ( x - 100 ).

Finally: 100 + 0.8 (x - 100) = 250.