Answer:
36 pencils
Step-by-step explanation:
Let h and p represent the number of highlighters and the number of pencils, respectively.
Then h + p = 45, and h = 45 - p.
Tom paid a total of $30 for these supplies, with ($2/highligher)(h) + ($0.333/pencil) adding up to that amount.
substituting 45 - p for h in 2h + 0.333p = 30, we get:
2(45 - p) + 0.333p = 30, or
90 - 2p + 0.333p = 30
Combine the constants: 60 = 2p - 0.333p, or 60 = 1.667p
Then p = 60/1.667 = 35.9928, or 36.
Tom bought 36 pencils for $12, and 45-36, or 9, highlighters for $18, for a total purchase of $30. This shows that these calculations are correct.
