Winona and Takoda are shopping for a present for their mother. There is no sales tax in their state. Write two expressions in terms of d to show how much Winona and Takoda would pay in total if they buy their mother the set of power tools. Power tools shows d for cost and 15% discount.

Question

I wrote this as one expression but don't know if it's right.
0.85d=0.9d-4.5
0.85d-0.9d=0.9d-45-0.9d
-0.15=4.5.

Can you check this and show me a second expression?

Answer 1

Let's clarify how to calculate the total cost of the power tools after applying the discount.

You mentioned that the power tools cost $d$ and that there is a 15% discount.

First Expression

To find the total cost after applying a 15% discount, we can start with the original price $d$:

1. Calculate the discount: The 15% of $d$ is $0.15d$.
2. Subtract the discount from the original price: $$\text{Total Cost}=d-0.15d=0.85d.$$

Second Expression

Another way to express the total cost after the discount would be to directly calculate the remaining percentage of the cost that they would pay:

1. Calculate the percentage of the price they'll pay: After a 15% discount, they will pay 85% of the original cost. Thus: $$\text{Total Cost}=0.85\cdot d.$$

Both expressions represent the same calculation and the final cost after the discount:

1. First Expression: $0.85d$
2. Second Expression: $d\cdot (1-0.15)=d\cdot 0.85=0.85d$

Thus, both expressions correctly give the total amount Winona and Takoda would pay for the power tools. Your original expression $0.85d=0.9d-4.5$ does not correctly represent the situation; the correct expressions are simply $0.85d$.