Final answer:
Uche's pumping rate of 18 liters per minute is equivalent to 300 milliliters per second after conversion.
Step-by-step explanation:
To convert Uche's pumping rate of gasoline from liters per minute to milliliters per second, we must recognize that there are 1,000 milliliters in 1 liter. Therefore, 18 liters per minute is the same as 18,000 milliliters per minute. To find the rate in milliliters per second, divide this number by 60, as there are 60 seconds in a minute.
18 liters/minute * 1,000 milliliters/liter = 18,000 milliliters/minute
18,000 milliliters/minute ÷ 60 seconds/minute = 300 milliliters/second