The marks of 15 students in an examinations are
25,19,17,24,23,29,31,40,19,20,22,26,17,35,21.
find the median score.

Answer

To find the median score of the given marks of 15 students, we will follow these steps:

### Step 1: Arrange the data in ascending order.
The given marks are:
25, 19, 17, 24, 23, 29, 31, 40, 19, 20, 22, 26, 17, 35, 21.

Arranging these marks in ascending order, we get:
17, 17, 19, 19, 20, 21, 22, 23, 24, 25, 26, 29, 31, 35, 40.

### Step 2: Determine the number of observations.
The total number of marks (n) is 15.

### Step 3: Identify if n is odd or even.
Since 15 is an odd number, we will use the formula for finding the median for an odd number of observations.

### Step 4: Use the median formula.
The formula for finding the median when n is odd is:
\[ \text{Median} = \text{Value of the } \left( \frac{n + 1}{2} \right)^{th} \text{ term} \]

Substituting n = 15 into the formula:
\[ \text{Median} = \text{Value of the } \left( \frac{15 + 1}{2} \right)^{th} \text{ term} = \text{Value of the } 8^{th} \text{ term} \]

### Step 5: Find the 8th term in the ordered list.
From our ordered list:
1. 17
2. 17
3. 19
4. 19
5. 20
6. 21
7. 22
8. 23 (This is the 8th term)
9. 24
10. 25
11. 26
12. 29
13. 31
14. 35
15. 40

The 8th term is 23.

### Conclusion:
Thus, the median score of the marks is **23**.

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