The equation best models the situation 100 + 0.8(x - 100) = 250.
The correct option is (D)
<h3>What is equation?</h3>
An equation in math is an equality relationship between two expressions written on both sides of the equal to sign.
The complete question is:
An ongoing promotion at a department store gives customers 20% 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?
A. 0.2x + 100 = 250
B. 0.8x + 100 = 250
C. 100 + 0.2(x - 100) = 250
D. 100 + 0.8(x - 100) = 250
Given:
Department store gives 20 % off the portion of the bill that is over 100 dollars.
Total bill = 250
let x is the amount of money she would have spent without the promotion.
Then, cost after discount applies = 0.8 ( x - 100 ).
Hence, the equation is 100 + 0.8 (x - 100) = 250.
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