Final answer:
Upon comparison, purchasing 150 feet of rope at $0.25 per foot, which totals to $37.50, is cheaper than buying enough 30-yard spools to cover the same length, which would cost $40.00. Hence, the per foot option is the better buy for John.
Step-by-step explanation:
To determine which is the better buy for John, we need to compare the cost of the 30-yard spool and the cost per foot of rope. First, we convert yards to feet knowing that 1 yard equals 3 feet:
30 yards * 3 feet/yard = 90 feet.
John needs 150 feet, so he would need to buy more than one 30-yard spool. Two spools would give him 180 feet, which is more than 150 feet, but for comparison purposes, we'll calculate the cost for 150 feet.
The cost of two 30-yard spools is:
2 * $24.00 = $48.00.
However, since John only needs 150 feet, the cost for exactly 150 feet at the spool's rate can be found by:
(150 feet / 90 feet per spool) * $24.00 = $40.00.
On the other hand, if John buys the rope at $0.25 per foot, the cost for 150 feet will be:
150 feet * $0.25/foot = $37.50.
Therefore, buying 150 feet of rope at $0.25 per foot is the more economical option compared to buying the 30-yard spools.