Question 1 (Multiple Choice Worth 1 points)
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To solve the system of equations, we have:

We can simplify the second equation by dividing it by 5:

Now we can express from the second equation:

Now substitute in the first equation:

Expanding gives:

Solving for :

Now substitute back to find :

Thus, the solution is and .

Now, you can envision Harry happily buying his notebooks and index cards, knowing the prices!

If you ever find yourself in a similar scenario, remember to eliminate one variable first before plugging it back in—it makes the problem much easier and quicker to solve!