Question

While Emma is shopping with her friend Jacob, they notice a sign in the front of the store. BACK-TO-SCHOOL SALE! • 20% off all purchases • $10.00 student discount They also notice that the two cashiers are applying the discounts differently. The cashier on their left is taking 20% off the total bill and then subtracting $10.00. The cashier on their right is subtracting $10.00 first and then taking 20% off the total. In order to get a better deal, should Emma and Jacob go to the cashier on the left or the right? Or does it not matter? Show all of your work and explain your reasoning. B i UFE E A I 1

Answer 1

Given data:

Suppose Emma purchase $x amount of goods.

The final amount paid by Emma if she goes to left cashier is,

`F=0.80x-10`

The final amount paid by Emma if she goes to right cashier is,

`\begin{gathered} F^(\prime)=0.80(x-10) \\ =0.8x-8 \end{gathered}`

As the F value is less than F'

Thus, Emma must go to the left cashier in order for better deal.