1. **Problem 1:** Nayeon won 40 lollipops and gave 2 to every student in her math class. She has at least 7 left.
2. **Write the inequality:** Let $x$ be the number of students. The total lollipops given away is $2x$. Since she has at least 7 left, the inequality is:
$$40 - 2x \geq 7$$
3. **Solve the inequality:**
$$40 - 2x \geq 7$$
Subtract 40 from both sides:
$$\cancel{40} - 2x - \cancel{40} \geq 7 - 40$$
$$-2x \geq -33$$
Divide both sides by $-2$ and reverse the inequality sign because dividing by a negative number reverses inequality:
$$x \leq \frac{-33}{-2}$$
$$x \leq 16.5$$
Since $x$ must be a whole number, the maximum number of students is 16.
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4. **Problem 2:** More than 450 students went on a field trip. Ten vans were filled, and 5 more students traveled in a car.
5. **Write the inequality:** Let $y$ be the number of students per van. Total students in vans is $10y$, plus 5 more in a car, total more than 450:
$$10y + 5 > 450$$
6. **Solve the inequality:**
$$10y + 5 > 450$$
Subtract 5 from both sides:
$$\cancel{10y} + 5 - 5 > 450 - 5$$
$$10y > 445$$
Divide both sides by 10:
$$y > \frac{445}{10}$$
$$y > 44.5$$
Since $y$ must be whole, minimum number of students per van is 45.
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7. **Problem 3:** Maloi spent 26 pesos on a magazine and five stationaries. The magazine costs 4.
8. **Write the inequality:** Let $s$ be the cost of each stationary. Total cost is magazine plus 5 stationaries, which should not exceed 26:
$$4 + 5s \leq 26$$
9. **Solve the inequality:**
$$4 + 5s \leq 26$$
Subtract 4 from both sides:
$$\cancel{4} + 5s - \cancel{4} \leq 26 - 4$$
$$5s \leq 22$$
Divide both sides by 5:
$$s \leq \frac{22}{5}$$
$$s \leq 4.4$$
So, the maximum cost of each stationary is 4.4 pesos.
**Final answers:**
1A. $40 - 2x \geq 7$
1B. $x \leq 16$
2A. $10y + 5 > 450$
2B. $y > 44.5$, minimum $y=45$
3A. $4 + 5s \leq 26$
3B. $s \leq 4.4$
Linear Inequalities 69Dc51
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