Associated Topics || Dr. Math Home || Search Dr. Math

### Finding Speed, Distance, and Time

```Date: 10/31/2002 at 09:07:29
From: Valerie Lynch
Subject: Science

Time = distance/speed. Does this symbol (/) mean that distance divided
by speed will give you time?
```

```
Date: 10/31/2002 at 10:11:58
From: Doctor Ian
Subject: Re: Science

Hi Valerie,

In a manner of speaking, yes.  We _define_ speed as distance divided
by time,

speed = distance / time

but once we have the equation, we can use any of its variations,

speed    = distance / time

distance = speed * time

time     = distance / speed

to compute any one of the quantities when we happen to know the other
two.

For example, suppose we drive for 2 hours at 30 miles per hour, for a
total of 60 miles. If we know the time and the speed, we can find the
distance:

2 hours * 30 miles/hour = 60 miles

If we know the time and the distance, we can find the speed:

60 miles / 2 hours = 30 miles/hour

If we know the speed and the distance, we can find the time:

60 miles / (30 miles/hour) = 2 hours

It's a little like having a family of multiplication facts, e.g.,

12 = 3 * 4

3 = 12 / 4

4 = 12 / 3

Does this make sense?

- Doctor Ian, The Math Forum
http://mathforum.org/dr.math/
```
Associated Topics:
Middle School Equations

Search the Dr. Math Library:

 Find items containing (put spaces between keywords):   Click only once for faster results: [ Choose "whole words" when searching for a word like age.] all keywords, in any order at least one, that exact phrase parts of words whole words

Submit your own question to Dr. Math
Math Forum Home || Math Library || Quick Reference || Math Forum Search