I only own blue blankets and red blankets. 8 out of every 15 blankets I have are red. | MathCelebrity Forum

I only own blue blankets and red blankets. 8 out of every 15 blankets I have are red.

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I only own blue blankets and red blankets. 8 out of every 15 blankets I have are red. If have i 45 blankets, how many are blue?

If 8 out of 15 blankets are red, then 15 - 8 = 7 are blue
So 7 out of every 15 blankets are blue.

Set up a proportion of blue blankets to total blankets where b is the number of blue blankets in 45 blankets
7/15 = b/45

Cross multiply:
If 2 proportions are equal, then we can do the following:
Numerator 1 * Denominator 2 = Denominator 1 * Numerator 2
15b = 45 * 7
15b = 315

To solve for b, divide each side of the equation by 15:
15b/15 = 315/15

Cancel the 15's on the left side and we get:
b = 21
 
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