Ethanol Concentration in Gasoline

The video tutorial explains how to determine the volume of gasoline with a 25% ethanol concentration needed to be added to a partially filled tank to achieve a 20% ethanol concentration. It begins by explaining the relationship between concentration and volume, calculates the initial ethanol volume, sets up an equation for the desired concentration, and solves it to find the required volume of gasoline to add.

What is the initial ethanol concentration in the partially filled tank?

• 25%

• 30%

• 20%

• 18%

How is concentration generally calculated?

• Volume of ingredient divided by total volume

• Volume of ingredient multiplied by total volume

• Total volume minus volume of ingredient

• Total volume divided by volume of ingredient

What is the initial volume of ethanol in the tank?

• 5.4 liters

• 9 liters

• 7.5 liters

• 6 liters

What variable is used to represent the volume of gasoline to be added?

• z

• y

• v

• x

What is the desired ethanol concentration after adding more gasoline?

• 30%

• 25%

• 18%

• 20%

What is the equation used to find the new ethanol concentration?

• 0.18 = (5.4 + 0.25v) / (30 + v)

• 0.25 = (5.4 + 0.2v) / (30 + v)

• 0.3 = (5.4 + 0.2v) / (30 + v)

• 0.2 = (5.4 + 0.25v) / (30 + v)

What is the value of 'v' that solves the equation?

• 18 liters

• 15 liters

• 10 liters

• 12 liters

What is the new total volume of gasoline after adding the calculated volume?

• 45 liters

• 42 liters

• 48 liters

• 40 liters

What is the new ethanol concentration after adding 12 liters of gasoline?

• 18%

• 20%

• 22%

• 25%

What is the concentration of ethanol in the gasoline being added?

• 25%

• 20%

• 30%

• 18%