# HiSET: Math : Proportional relationships

## Example Questions

### Example Question #1 : Multi Step Real World And Mathematical Problems

An electronics store is having a sale and offering  off the regular prices of all laptop computers. If the sale price for a certain laptop is , what is the regular price of the laptop?

Explanation:

Notice that  is the price after the  discount. Therefore, the sale price of  is  of the regular price (or  times the regular price). The regular price can be represented as , or  times the regular price.

First, set up a proportion describing the problem, using  to represent the unknown quantity, the regular price:

Next, cross multiply:

Finally, divide both sides by  to solve for :

Therefore, the regular price is .

### Example Question #1 : Multi Step Real World And Mathematical Problems

3 sticks of butter weigh 12 ounces combined. Using this information, determine the weight of 7 sticks of butter.

Explanation:

Set up a proportional relationship, using  to represent the unknown quantity (the weight of 7 sticks of butter):

Cross multiply:

Finally, divide both sides to solve for :

### Example Question #1 : Multi Step Real World And Mathematical Problems

If  is inversely related to  and  and  is directly related to , which formula describes the relationship between  and ?

Explanation:

To say that  is inversely related to  is to say .

To say that  is directly related to  is to say .

Thus, to say  is inversely related to  and  and  is directly related to  is to say