Final answer:
To convert 16 oz. of 30 index fluid to gallons of a 2.5% solution, divide 16 by 128 and multiply the result by 2.5%.
Step-by-step explanation:
To find the number of gallons in a 2.5% solution of 16 oz. of 30 index fluid, we first need to convert ounces to gallons. Since there are 128 fluid ounces in a gallon, we can divide 16 by 128 to get the number of gallons. Next, we multiply the number of gallons by the 2.5% concentration to find the amount of the solution in gallons. Therefore, the answer is 16/128 * 2.5 = 0.3125 gallons of a 2.5% solution.