18. One gallon of cleaning solution requires 6 oz of ammonia. If the maintenance department needs 120 gallons of solution to clean all the floors, how much ammonia is needed?
Answer: C
720 oz of ammonia is needed.
To prepare 120 gallons of cleaning solution, a total of 720 oz of ammonia is required, calculated by multiplying the amount of ammonia needed for one gallon by the total gallons needed.
A) 20 oz
This option is incorrect because it vastly underestimates the amount of ammonia needed. Since each gallon requires 6 oz of ammonia, the total required for 120 gallons would be much greater than 20 oz.
B) 20 gallons
This option is incorrect as it misinterprets the measurement of ammonia. The requirement is for ounces, not gallons, making 20 gallons an irrelevant and incorrect response.
C) 720 oz
This option is correct. To find the total ammonia needed, we multiply 6 oz by the number of gallons: 6 oz/gallon * 120 gallons = 720 oz. Hence, 720 oz is indeed the correct amount of ammonia needed.
D) 720 gallons
This option is incorrect because it mistakenly presents the amount of ammonia in gallons rather than ounces. The calculation shows the requirement in ounces, making 720 gallons an incorrect representation of the necessary ammonia.
Conclusion
The calculation clearly indicates that 720 oz of ammonia is necessary for 120 gallons of cleaning solution. All other options either miscalculate or misrepresent the required units, confirming that option C is the only viable answer based on the problem's context.