Final answer:
To find the cost of 3 calculators given the cost of 5 calculators, divide the total cost by 5 and multiply the result by 3.
Step-by-step explanation:
To find the cost of 1 calculator, we divide the total cost ($57.50) by the number of calculators (5). This gives us the cost per calculator: $57.50 / 5 = $11.50. To find the cost of 3 calculators, we multiply the cost per calculator ($11.50) by the number of calculators (3). This gives us the total cost: $11.50 * 3 = $34.50.