Question

Please explain to me how to know whether to put the x up or down

Answer 1

Case: Direct Proportion

Given: Several cases of direct proportions.

3 ounces of perfume for $99

8 ounces will be for x dollars

Required: To find the value of x in dollars

Method:

`\begin{gathered} 3\text{ ounces for 99 dollars} \\ 8\text{ ounces for x dollars} \\ 3\equiv\text{ 99} \\ 8\text{ = x} \\ \text{Cross multiplying} \\ 3\text{ }*\text{ x = 8 }*\text{ 99} \\ 3x\text{ =792} \\ \text{Dividing both sides by 3} \\ x\text{ = 264} \end{gathered}`

Final answer:

8 ounces of perfume will cost $264