Question

Ella Buys a book and a pen for $14. The cost of the book is two dollars more than twice the cost of the pen. Write a system of linear equations for this situation. Then find the cause of each item. Let's actually present the cost of the pen and like why are you present the cost of the book.

Answer 1

Answer: The book costs $10 and the pen costs $4✔️

Explanation:

Let B the cost of the book and let P the cost of the pen.

Then we know:

The book and the pen cost $14:

B + P = $14 } Equation 1

We also know:

The cost of the book is two dollars more than twice the cost of the pen.

B = 2P + $2 } Equation 2

Now we can substitute the value of B from the equation 2 in the equation 1:

2P + $2 + P = $14

3P = $14 - $2 = $12

P = $12/3 = $4 , cost of the pen

Since we know the value of B from the equation 2, we can calculate B:

B = 2P + $2 = 2x$4 + $2 = $8 + $2 = $10 , cost of the book

Answer: The book costs $10 and the pen costs $4✔️

Verify

We can substitute these values in equations 1 and 2 and check the results:

B + P = $14 } Equation 1

$10 + $4 = $14 ✔️check!

B = 2P + $2 } Equation 2

$10 = 2x$4 + $2 = $8 + $2 = $10 ✔️check!

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