To determine the number of gallons of gas Mrs. Ebert would need for the total trip, we can set up a proportion:
552 miles/23 gallons = 840 miles/x gallons
To find x, we can cross-multiply and solve for x:
552x = 840 * 23
Dividing both sides of the equation by 552:
x = (840 * 23) / 552
x ≈ 35.17
Therefore, Mrs. Ebert would need approximately 35.17 gallons of gas for the total trip.