Answer:
 The total cost is: $13.50 
Explanation:
Given
Item cost = $12.50
Sales tax = 8% = 0.08
To determine
Total cost = ?
Sales amount can be calculated by multiplying item cost 12.50 by sales tax 8% or 0.08.
Sales amount = Item cost × 0.08
 = 12.50 × 0.08
 = $1 
The total cost can be calculated by adding the item cost plus the Sales amount.
Total cost = Item cost + Sales amount
 = 12.50 + 1
 = $13.50
 Therefore,
 The total cost is: $13.50