The total cost of Anja's trip to the dentist was [tex]$\$[/tex] 628.35[tex]$. She paid a flat fee of $[/tex]\[tex]$ 89.95$[/tex], which included the checkup and cleaning, and then had 4 cavities filled, each of which cost the same amount.

Which shows the correct equation and value of [tex]$x$[/tex], the cost of each cavity filling?

A. [tex]$4x + 89.95 = 628.35 ; x = \$[/tex] 134.80[tex]$
B. $[/tex]4(89.95) + x = 628.35[tex]$
C. $[/tex]4x + 89.95 = 628.35 ; x = \[tex]$ 134.60$[/tex]
D. [tex]$4(89.95) + x = 628.35 ; x = \$[/tex] 538.40$



Answer :

To determine the correct equation and the value of [tex]\( x \)[/tex], the cost of each cavity filling, let's break down the problem logically and solve it step by step.

### Given Information:
- Total cost of the trip: \[tex]$628.35 - Flat fee for checkup and cleaning: \$[/tex]89.95
- Number of cavities filled: 4

### Step 1: Set up the Equation
Let's denote the cost of filling one cavity as [tex]\( x \)[/tex].

The total cost is the sum of the flat fee and the cost of filling the cavities. Since there are 4 cavities, the cost of filling them would be [tex]\( 4x \)[/tex].

Thus, the equation can be set up as:
[tex]\[ \text{Total cost} = \text{Flat fee} + \text{Cost per cavity} \times \text{Number of cavities} \][/tex]
[tex]\[ 628.35 = 89.95 + 4x \][/tex]

This matches the equation:
[tex]\[ 4x + 89.95 = 628.35 \][/tex]

### Step 2: Solve for [tex]\( x \)[/tex]
To find [tex]\( x \)[/tex], we need to isolate [tex]\( x \)[/tex] in the equation:
[tex]\[ 4x + 89.95 = 628.35 \][/tex]

Subtract the flat fee from the total cost:
[tex]\[ 4x = 628.35 - 89.95 \][/tex]
[tex]\[ 4x = 538.40 \][/tex]

Divide both sides by 4 to solve for [tex]\( x \)[/tex]:
[tex]\[ x = \frac{538.40}{4} \][/tex]
[tex]\[ x = 134.60 \][/tex]

### Step 3: Verify the Choices
Let's compare our equation and the calculated value of [tex]\( x \)[/tex] with the given choices:

1. [tex]\( 4x + 89.95 = 82835 ; x = 13480 \)[/tex]
2. [tex]\( 4(8995) + x = 628.35 \)[/tex]
3. [tex]\( 4x + 89.95 = 628.35 ; x = 179.58 \)[/tex]
4. [tex]\( 4(89.95) + x = 628.35 ; x = 538.40 \)[/tex]

The correct equation from our setup is:
[tex]\[ 4x + 89.95 = 628.35 \][/tex]

The correct value of [tex]\( x \)[/tex] we calculated is:
[tex]\[ x = 134.60 \][/tex]

None of the given choices present the correct combination of the equation and the value, but our calculations confirm:
[tex]\[ 4x + 89.95 = 628.35 ; x = 134.60 \][/tex]

Given the curriculum and typical response format, always double-check your input data and parameters if you encounter discrepancies.