# If an object went from #0.96g " to " 0.69g# would the percent change be #-28# or #-39# and why?

##### 3 Answers

#### Explanation:

Always remember that a percentage change of two different values is the **difference** over the **original**.

The **difference** in the change is

Now, divide this value by the **original** value:

(Note, usually, the percentage change is taken to be the absolute value, i.e. ignore the sign to get

#### Explanation:

The ratio is

putting these values into the equation gives

Multiplying both sides by

Because the

#### Explanation:

The first clue is the negative sign, which indicates a decrease.

The mass changed from

This means that the

The amount of the decrease is

Determine what percent this is **of the original amount**.

As the change is a decrease this can be shown as

If the change was calculated using the final amount the answer is

However, this is incorrect.