1. **Problem statement:** Given the ordered numbers $x, (x+1), 5, (2x+1), (y+2), 7, 8,$ and $(3x+2)$, the mean is 6.5 and the median is 7. Find $x$ and $y$.
2. **Mean formula:** The mean of $n$ numbers $a_1, a_2, \ldots, a_n$ is given by
$$\text{Mean} = \frac{a_1 + a_2 + \cdots + a_n}{n}$$
3. **Calculate the mean:** There are 8 numbers, so
$$\frac{x + (x+1) + 5 + (2x+1) + (y+2) + 7 + 8 + (3x+2)}{8} = 6.5$$
4. **Simplify numerator:**
$$x + x + 1 + 5 + 2x + 1 + y + 2 + 7 + 8 + 3x + 2 = (x + x + 2x + 3x) + (1 + 5 + 1 + 2 + 7 + 8 + 2) + y = 9x + 26 + y$$
5. **Set up equation:**
$$\frac{9x + y + 26}{8} = 6.5$$
6. **Multiply both sides by 8:**
$$\cancel{8} \times \frac{9x + y + 26}{\cancel{8}} = 6.5 \times 8$$
$$9x + y + 26 = 52$$
7. **Rearrange:**
$$9x + y = 52 - 26$$
$$9x + y = 26 \quad \quad (1)$$
8. **Median definition:** The median is the middle value when numbers are ordered. Since there are 8 numbers (even), the median is the average of the 4th and 5th numbers in the ordered list.
9. **Order the numbers:** We know median is 7, so the 4th and 5th numbers average to 7.
10. **Arrange numbers in increasing order:** The numbers depend on $x$ and $y$. We test possible orderings consistent with median 7.
11. **Assuming $x < 5$ (since 5 is fixed), the numbers are:**
$$x, x+1, 5, 2x+1, y+2, 7, 8, 3x+2$$
12. **Median is average of 4th and 5th numbers:**
$$\frac{\text{4th} + \text{5th}}{2} = 7$$
13. **Try 4th = $2x+1$, 5th = $y+2$:**
$$\frac{2x + 1 + y + 2}{2} = 7$$
$$2x + y + 3 = 14$$
$$2x + y = 11 \quad \quad (2)$$
14. **Solve system of equations (1) and (2):**
$$9x + y = 26$$
$$2x + y = 11$$
15. **Subtract second from first:**
$$(9x + y) - (2x + y) = 26 - 11$$
$$7x = 15$$
$$x = \frac{15}{7}$$
16. **Find $y$ using (2):**
$$2 \times \frac{15}{7} + y = 11$$
$$\frac{30}{7} + y = 11$$
$$y = 11 - \frac{30}{7} = \frac{77}{7} - \frac{30}{7} = \frac{47}{7}$$
17. **Final answers:**
$$x = \frac{15}{7} \approx 2.14$$
$$y = \frac{47}{7} \approx 6.71$$
Mean Median F27Faf
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.