Using Ratios to Solve Application Problems
Use the given information and unit analysis to solve the proportional problems.
Chase is an office manager and needed to purchase blue and black pens for his office. He bought 7\displaystyle {7} blue pens for every 6\displaystyle {6} black pens. Use this information to find the following ratios. Write your answers in fraction form.
Ratio of Blue Pens to Black Pens   blueblack\displaystyle \frac{\text{blue}}{\text{black}}
Ratio of Black Pens to Blue Pens   blackblue\displaystyle \frac{\text{black}}{\text{blue}}

Ratio of Blue Pens to Pens of Either Color   blueeither color\displaystyle \frac{\text{blue}}{\text{either color}}
Ratio of Black Pens to Pens of Either Color   blackeither color\displaystyle \frac{\text{black}}{\text{either color}}
Suppose Chase bought 24\displaystyle {24} black pens. How many blue pens did he buy?

Unit Analysis: blueblack⋅black total=blue total\displaystyle \frac{\text{blue}}{\text{black}}\cdot\text{black total}=\text{blue total} 		blue total\displaystyle \text{blue total}
Suppose Chase bought 35\displaystyle {35} blue pens. How many black pens did he buy?

Unit Analysis: blackblue⋅blue total=black total\displaystyle \frac{\text{black}}{\text{blue}}\cdot\text{blue total}=\text{black total} 		black total\displaystyle \text{black total}
Suppose Chase bought a total of 39\displaystyle {39} pens. How many blue pens did he buy?

Unit Analysis: blueeither color⋅either color total=blue total\displaystyle \frac{\text{blue}}{\text{either color}}\cdot\text{either color total}=\text{blue total} 		blue total\displaystyle \text{blue total}
Suppose Chase bought a total of 52\displaystyle {52} pens. How many black pens did he buy?

Unit Analysis: blackeither color⋅either color total=black total\displaystyle \frac{\text{black}}{\text{either color}}\cdot\text{either color total}=\text{black total} 		black total\displaystyle \text{black total}

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