Final answer:
To find the cost of potatoes, multiply the weight in kg by the unit price of $0.50/kg, derived from the given information that 10 kg costs $5.
Step-by-step explanation:
The question requires the creation of a formula to calculate the cost of potatoes. Given that a 10 kg bag of potatoes costs $5, we can establish a unit price for the potatoes by dividing the total cost by the weight. The unit price per kilogram would be $5 divided by 10 kg, which is $0.50/kg. Therefore, the formula for the cost of potatoes can be written as Cost = $0.50 × weight in kg.
To give an example: If you were to buy 7.56 kg of potatoes at this unit price, using the formula you would multiply 7.56 by $0.50 to get the total cost.
For example: Cost = $0.50/kg × 7.56 kg = $3.78.