A driver just filled the car's gas tank with 18 liters of gasohol, a mixture consisting of 5% ethanol and 95% gasoline. If the car runs best on a mixture consisting of 10% ethanol and 90% gasoline, how many liters of ethanol must be added into the gas tank for the car to achieve optimum performance? Choices.
A) 1 B) 1.5 C) 1.8 D) 2.4 E) 3
Let x be the number of liters of ethanol added to the gas tank.   0.05(18) + x = 0.1(18+x)   0.9x = 1.8 - 0.9   x = 1 liter   The answer is 1.
<result>A</result>
A driver just filled the car's gas tank with 18 liters of gasohol, a mixture consisting of 5% ethanol and 95% gasoline. If the car runs best on a mixture consisting of 10% ethanol and 90% gasoline, how many liters of ethanol must be added into the gas tank for the car to achieve optimum performance?