Let the cost of each of the first three tires be \( x \). According to the holiday deal, the cost of the fourth tire is $5. Therefore, the total cost of the tires can be expressed as:
\[ 3x + 5 = 237.50 \]
To find \( x \), first, let's subtract $5 from both sides:
\[ 3x = 237.50 - 5 \] \[ 3x = 232.50 \]
Next, divide both sides by 3:
\[ x = \frac{232.50}{3} = 77.50 \]
Thus, the cost of each of the first three tires is $77.50.