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I need help with this please it’s revisiting proportional relationships

I need help with this please it’s revisiting proportional relationships-example-1

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In order to calculate the cost of 7.5 lbs of walnuts, we can use the following rule of three, knowing that 3/4 lbs have a cost of $3.45:


\begin{gathered} \text{weight}\to\text{ cost} \\ (3)/(4)\text{ lbs}\to3.45 \\ 7.5\text{ lbs}\to x \end{gathered}

Now, we can write the following proportion and solve for x:


\begin{gathered} ((3)/(4))/(7.5)=(3.45)/(x) \\ x\cdot(3)/(4)=7.5\cdot3.45 \\ x=(7.5\cdot3.45\cdot4)/(3) \\ x=34.5 \end{gathered}

Therefore the cost is $34.50.

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