at noon, a cargo van crosses an intersection at 30 mph. At 12:30 pm, a car crosses the same intersection traveling in the opposite direction. At 1 pm, the van and car are 54 miles apart. How fast is the car traveling?

Question

I know the answer is 48 mph, but can you set it up for me?

Let's do it by logic and you set it up.
The van traveled for 1 hour at 30 mph so it will travel 30 miles.
At the end of 1 hour, the van and car were 54 miles apart; therefore, the van has traveled 54-30 = 24 miles.
The van traveled 24 miles in 1/2 hour which is 48 miles in 1 hour.

I hope the gets you started.