Final answer:
To find out how much fuel is in Donna's car now, we add the amount she just put in to the amount that was already in the car. The total amount of fuel in Donna's car now is 24.56 gallons.
Step-by-step explanation:
To find out how much fuel is in Donna's car now, we need to add the amount she just put in to the amount that was already in the car.
Donna put in 20.76 gallons of fuel and there were already 3.8 gallons in the car. So, the total amount of fuel in Donna's car now is 20.76 + 3.8 = 24.56 gallons.