Answer: N=3
Step-by-step explanation:
Let's represent notebooks with "N" and pencils with "P".
Then,
N + P = 4.50
Since N =2P, we can substitute that directly into the equation:
(2P) + P = 4.50
3P = 4.50 (divide both sides by 3)
P = 1.50
Now that we have P, we can in turn substitute that into the equation.
N + (1.50) = 4.50
N = 3.00