Final answer:
Isaac's parents paid 10.16% of their rental cost for utilities, calculated by dividing the utilities cost by the total rent and multiplying by 100.
Step-by-step explanation:
The question asks what percent of the rental cost was for utilities in Isaac's parents' business. To answer this, we calculate the percentage by dividing the cost of utilities by the total rental cost and then multiplying the result by 100. So, we take $325 for utilities and divide by the total rental cost of $3,200 per month. The calculation is as follows:
($325 ÷ $3,200) × 100 = 10.15625%
Therefore, the percentage of the rental cost that was for utilities is approximately 10.16%.