Class: Eight
First Terminal Examination - 20
Subject: Optional Mathematics
Time: 2 hrs

Group-A

1. If [tex](x, x+y) = (2, 7)[/tex], find [tex]x[/tex] and [tex]y[/tex].

2. Find the median from the following marks:
27, 28, 30, 18, 29, 16, 25, 23, 2

3. Find the mean of the numbers:
48, 38, 42, 38



Answer :

Sure, let's solve each part of the question step-by-step.

### Part 1: Finding [tex]\(x\)[/tex] and [tex]\(y\)[/tex]

Given the ordered pair [tex]\((x, x + y) = (2, 7)\)[/tex],

1. We know that [tex]\(x = 2\)[/tex].
2. Substitute [tex]\(x = 2\)[/tex] into the equation [tex]\(x + y = 7\)[/tex]:
[tex]\[ 2 + y = 7 \][/tex]
3. Solving for [tex]\(y\)[/tex]:
[tex]\[ y = 7 - 2 \][/tex]
[tex]\[ y = 5 \][/tex]

Thus, [tex]\(x = 2\)[/tex] and [tex]\(y = 5\)[/tex].

### Part 2: Finding the median of the given marks

Given the marks: 27, 28, 30, 18, 29, 16, 25, 23, 2.

1. First, arrange the marks in ascending order:
[tex]\[ 2, 16, 18, 23, 25, 27, 28, 29, 30 \][/tex]
2. The number of marks, [tex]\(n\)[/tex], is 9, which is an odd number. Therefore, the median is the middle number in the sorted list.
3. The position of the median is given by:
[tex]\[ \text{Median position} = \frac{n + 1}{2} = \frac{9 + 1}{2} = 5 \][/tex]
4. The 5th number in the ordered list is:
[tex]\[ 25 \][/tex]

Thus, the median is [tex]\(25\)[/tex].

### Part 3: Finding the mean of given numbers

Given the numbers: 48, 38, 42, 38.

1. First, find the sum of the numbers:
[tex]\[ 48 + 38 + 42 + 38 = 166 \][/tex]
2. Count the number of values, which is 4.
3. Calculate the mean by dividing the sum by the number of values:
[tex]\[ \text{Mean} = \frac{166}{4} = 41.5 \][/tex]

Thus, the mean of the numbers is [tex]\(41.5\)[/tex].

### Summary:

1. [tex]\(x = 2\)[/tex], [tex]\(y = 5\)[/tex].
2. The median of the marks is [tex]\(25\)[/tex].
3. The mean of the numbers is [tex]\(41.5\)[/tex].

These are the detailed solutions to each part of the question.