1. **Solve the inequality** $\frac{r}{2} + 15 > 45$.
2. Subtract 15 from both sides:
$$\frac{r}{2} > 45 - 15$$
$$\frac{r}{2} > 30$$
3. Multiply both sides by 2 to isolate $r$:
$$r > 60$$
4. **Interpretation:** The solution is all values of $r$ greater than 60, which matches the graph with an open circle at 60 and arrow to the right.
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5. **Find the cost of 1 T-shirt given:**
$$2x + 3y = 45$$
$$2x + 4y = 52$$
where $x$ is the cost of one jumper and $y$ is the cost of one T-shirt.
6. Subtract the first equation from the second:
$$(2x + 4y) - (2x + 3y) = 52 - 45$$
$$2x - 2x + 4y - 3y = 7$$
$$y = 7$$
7. **Answer:** The cost of one T-shirt is 7.
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8. **Write down the inequality shown on the number line:**
The number line shows a filled circle at 20 and arrow to the right.
9. This corresponds to:
$$x \geq 20$$
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10. **Solve the inequality:**
$$7 > a - 5$$
11. Add 5 to both sides:
$$7 + 5 > a$$
$$12 > a$$
12. Rewrite as:
$$a < 12$$
13. The graph shows an open circle at 5 and arrow to the left, indicating $a < 5$, which is a stricter condition than $a < 12$.
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14. **Solve the simultaneous equations:**
$$3x + 7y = 54$$
$$3x + 3y = 6$$
15. Subtract the second equation from the first:
$$(3x + 7y) - (3x + 3y) = 54 - 6$$
$$3x - 3x + 7y - 3y = 48$$
$$4y = 48$$
$$y = 12$$
16. Substitute $y=12$ into the second equation:
$$3x + 3(12) = 6$$
$$3x + 36 = 6$$
$$3x = 6 - 36$$
$$3x = -30$$
$$x = -10$$
17. **Solution:** $x = -10$, $y = 12$.
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**Final answers:**
- Inequality solution: $r > 60$
- Cost of one T-shirt: 7
- Number line inequality: $x \geq 20$
- Inequality solution: $a < 12$
- Simultaneous equations solution: $x = -10$, $y = 12$
Inequalities Simultaneous
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