Answer:
Notebooks: $2.75 each; pens: $1.10 each
Step-by-step explanation:
Let n and p represent the unit cost of notebooks and the unit cost of pens.
Then 3n + 2p = $10.45, and 4n + 6p = $17.60.
Let's use elimination by addition/subtraction to find n and p.
Multiplying the first equation by -3, we get -9n - 6p = -$31.35
and then combine this with the second: 4n + 6p = $17.60
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Then, -5n = -$13.75
Dividing both sides by 55, we get n = $13.75 / 5, so we now know that n = $2.75. Each notebook costs $2.75.
Subbing $2.75 for n in the first equation, we get:
3($2.75) + 2p = $10.45, or
$8.25 + 2p = $10.45
Solving for p, we get p = $2.20 / 2 = $1.10.
Each pen costs $1.10.
