Question

Answer the question below* 1 point A grocery store offers a service where customers can place an order and have their groceries delivered to their home for an additional fee. The equation y = 1.1x can be used to find y, the total cost in dollars for x, the grocery cost in dollars. Arlyn has groceries delivered for a total cost of $119.90. He says his grocery cost must be $108.90. Is Arlyn correct? Explain your reasoning. Yes O No​

Answer 1

No.

Explanation:

For starters, it says the representation of the grocery cost is x, but we have the equation y=1.1x. So, because 1x+0.1x=1.1x, we can infer that 0.1x is equal to our delivery cost, which we can call z.

Now we have two equations. y=x+z, and z=0.1x.

For this problem, we don't necessarily have to find the actual cost: just prove whether or not Arlyn is correct or incorrect by plugging in numbers for variables. So we can plug in our values of 119.90 (total value) and 108.90 (supposed grocery cost value) into our equations.

We now have 119.90=108.90+z, and z=0.1(108.90). First we can compute z=0.1(108.90). Since we know multiplying by 0.1 is the same as multiplying by 1/10, it's easy to get 108.90/10, which is 10.89. Now we can substitute 10.89 into our second equation for z, to get 119.90=108.90+10.89, where you get 119.90=119.79, which is not true. Therefore, Arlyn is incorrect, because $119.79 is not equal to $119.90.