Sanji buys a lot of health food from a company that charges 3% on each item for shipping. If he purchased a premium membership for $45 a year, the shipping would be free. He wants to know how much food he would have to buy each year so that the cost of the membership would be the same as the cost of the shipping charges without the membership. Which equation does this situation model?

- x+ 0.03=45
- x= 0.03x+45
- x+0.03x= x+45
- 1.03x=45

1 answer

To find out how much health food Sanji needs to buy for the membership cost to equal the shipping charges, we can set up an equation.

Let \( x \) be the total cost of the health food he buys in dollars. Without the membership, he pays 3% shipping on this amount, which can be expressed as \( 0.03x \). With the premium membership costing $45, we need to find when these two costs are equal:

\[ 0.03x = 45 \]

Now we can rearrange this equation to express it in a more standard form:

  1. Starting with \( 0.03x = 45 \)
  2. We can multiply both sides by \( \frac{1}{0.03} \) to solve for \( x \):

\[ x = \frac{45}{0.03} \]

This shows that the shipping charges will equal the membership cost when the total cost of the health food purchased is \( x \).

To model this situation, the correct equation from the options given is derived from the equation for the shipping charges:

If we manipulate the equation we started with, we can see that:

\[ 0.03x + 45 = 0 \ 0.03x + 45 = x \]

This is very similar to the provided options.

Among the options given, the equation that potentially represents this is:

  • 1.03x = 45

However, it is important to clarify that the first step reveals that the cost of health food should equal the membership cost, leading ultimately to

\[ x = 0.03x + 45 \]

Thus the correct choice from your list that best fits the model of the shipping charges between membership and non-membership is:

  • x = 0.03x + 45

This equation signifies that the total cost \( x \) is what you pay for the health food without the membership, equating it to the additional shipping cost plus the membership fee.