Rate x Time = Distance
In the OG quant review book, PS question number 23 asks: How many minutes does it take to travel 120 miles at 400 miles per hour? This is a simple question, and I got it right, but I really had to think it through to figure out what I needed to divide by what in order to solve it. I didn't remember the simple formula of r*t = d. So to set it up you just do 400mph * T = 120 miles. Then simply divide both sides by 400, and that gives you the time in the form of a fraction of an hour. Multiply it by 60 to get the minutes.