Question
The ratio of red to blue to black pens in a box is $3: 5: 7 .$ If all 75 pens in the box are one of these colors, how many are red?
Step 1
Let's denote the number of red pens as $3x$, the number of blue pens as $5x$, and the number of black pens as $7x$. Show more…
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