Arithmetic (Beginner) · Quick Reference

Speed, Distance & Time Cheat Sheet

Arithmetic (Beginner) · Lesson 17/21

In one line: speed, distance, and time are connected by one simple relationship that lets us solve for any one of them if we know the other two.

Key Ideas

1Core Relationship. Speed = Distance / Time. Rearranged: Distance = Speed x Time, and Time = Distance / Speed.

2Units. Speed is commonly measured in km/h or m/s. Be careful to keep units consistent before calculating.

3Average Speed. Average speed = Total distance / Total time (not simply the average of individual speeds unless times are equal).

4Relative Speed (Same Direction). When two objects move the same way, relative speed = difference of their speeds.

5Relative Speed (Opposite Directions). When two objects move toward each other, relative speed = sum of their speeds.

A car travels 180 km in 3 hours. Find its speed.

60 km/h

A train moves at 80 km/h for 2.5 hours. Find the distance covered.

200 km

Two cars start at the same point and travel in opposite directions at 50 km/h and 60 km/h. How far apart are they after 2 hours?

220 km

Speed = Distance / Time

Distance = Speed x Time

Time = Distance / Speed

Find speed if distance = 240 km and time = 4 hours.

60 km/h

Find distance if speed = 45 km/h and time = 2 hours.

90 km

Find time if distance = 150 km and speed = 50 km/h.

3 hours