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bone-shaped treats are five for 3:50 at Shelly store in Sarah wants to buy 12 she set up and solve this proportion to find how much they would cost describe her error and find the correct solution

bone-shaped treats are five for 3:50 at Shelly store in Sarah wants to buy 12 she-example-1

2 Answers

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Sarah multiplied the denominator by the denominator and the numerator by the numerator instead of finding the cross products. The equation should be 5x = 42, so the cost should be $8.40.

User Mikesl
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5 votes

Answer:

8.4 dollars

Explanation:

The error is in the resolution of the proportion. In fact, the initial proportion is correct:


(5)/(3.5)=(12)/(x)

where x is the total cost. However, the following step of the resolution is wrong. In fact, the correct resolution is the following:

- Multiplying by x on both sides:


(5x)/(3.5)=12

- Multiplying by 3.5 no both sides:


5 x = 12 \cdot 3.5 \\5x = 42

And now we can find x:


x=(42)/(5)=8.4

So, the total cost is 8.4 dollars.

User Luke
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6.0k points