Final answer:
Calculating the cost per inch of wire from the given information ($0.13 for 39 inches) and then using that unit rate to find out how many inches can be bought with $18, we determine that 5400 inches of wire can be purchased.
Step-by-step explanation:
The student is asking how many inches of wire can be purchased for $18 given that 39 inches of wire cost $0.13. This question involves finding the unit rate and then using that rate to calculate the quantity that corresponds to a different price. We'll do this by setting up a proportion where we compare the lengths of wire to their costs.
First, we find the cost per inch of wire by dividing the total cost by the number of inches: $0.13/39 inches. This gives us the unit price per inch. Then, we can multiply this unit price by the new cost ($18) to find the number of inches that can be purchased.
To simplify the calculation, the proportion looks like this:
- Cost per inch: $0.13 / 39 inches = $0.003333 per inch
- Inches for $18: $18 / $0.003333 per inch
Now we multiply to find the total length of wire that can be purchased:
$18 / $0.003333 per inch = 5400 inches of wire