The answer is: 45 sandals.
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Explanation:
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The ratio of:
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shoes : sandals = 8:5
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We want to know how many SHOES were sold; if 72 sandals were sold.
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→ 8:5 = x:72 ; in which "x" = number of shoes were sold;
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We can write this as:
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→ 8 / 5 = x / 72;
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→ Cancel the "8" to a "1"; and change the "72" to a "9"; since "8 * 9 = 72" ;
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→ and rewrite as: 1 / 5 = x / 9 ;
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→ SInce "1/5" = 0.2 ; write as: 0.2 = x / 9 ↔ (0.2) x = 9 ;
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→ Now, divide EACH side of the equation by "(0.2)" ; to isolate "x" on one side of the equation; and to solve for "x' ;
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→ (0.2) x / (0.2) = 9 / (0.2) ; → to get: 45.
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The answer is: 45 sandals.
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(Note: Ratio of 45 shoes to 72 sandals)