Answer:
Let's first find out how much work Ronald and Marco can do in one hour.
Ronald's rate = 1 car / 3 hours = 1/3 car per hour
Marco's rate = 1 car / 4 hours = 1/4 car per hour
Their combined rate would be the sum of their individual rates:
Combined rate = Ronald's rate + Marco's rate
= 1/3 car per hour + 1/4 car per hour
= 7/12 car per hour
This means that together, Ronald and Marco can wash and wax 7/12 of a car in one hour.
Now, let's use this combined rate to determine how long it would take them to wash and wax one car.
The formula for work is:
Work = Rate x Time
Since they want to wash and wax one car, we can plug in the values we found above and solve for time:
1 car = (7/12 car per hour) x Time
Time = 1 car / (7/12 car per hour)
Time = 12/7 hours
Therefore, it would take Ronald and Marco approximately 1 hour and 43 minutes (12/7 hours) to wash and wax one car if they worked together.