A truck driver drove 240 miles in 4 hours. What was the average speed?

Average speed = total distance ÷ total time = 240 miles ÷ 4 hours = 60 miles per hour. This is the basic rate formula: rate × time = distance, which rearranges to rate = distance ÷ time. The same formula handles many ASVAB problems: speed, work rate, flow rate, production rate. Three-variable problems can be set up: if you know any two of (distance, time, speed), you can find the third. Examples: at 60 mph, how long to drive 180 miles? Time = 180/60 = 3 hours. If you drove 2.5 hours at 50 mph, how far did you go? Distance = 50 × 2.5 = 125 miles. Memorize the relationship as a triangle: distance on top, rate and time on bottom — cover the one you want to find to see the operation.