Question

The value of a share of stock decreases in value at a rate of $1.20 hour during the first 3.5 hours of trading. How do you write and solve an equation to find the decrease in the value of the share of stock during that time?

Answer 1

The change is `-$3.00`

Explanation:

Did you know you can, and may, treat units of measurement in the same way you do the numbers. Very useful in applied maths, physics, engineering and so on.

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Looking at just the units as a guide to how to go about solving this.

The objective is to end up with just $

We are told that there is a decrease of $ per hour: written as `" "$/h`

So to change `$/h` into just `$` we multiply by `h`

So her have:

`$/hxxh" "->" "($1.20)/(1 h)xx3.5h`

`=>1.2xx3.5xx$/(cancel(h))xxcancel(h)`

`=> 3.00xx $` normally written as `$3.00`

As this is a decrease you could if you chose write this as

The change is `-$3.00`