Question

The table below shows the distribution of marks obtained by students in an examination. Calculate the value of x if the mean mark is 18.

Marks No. of students

5 6

10 4

15 6

20 12

25 x

30 4​

Answer 1

Answer:

The frequency distribution table for the given marks can se draw as

1.. The class interval (40-49) has the highest frequency and the class interval (90-99) has the lowest frequency.

2.. In the class interval (30-39), the lower limit is 30 - 0.5 = 29.5 and the upper limit is 39 + 0.5 = 39.5

Step-by-step explanation:

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Answer 2

$the \: value \: of \: x \: is \\ \frac{6 + 4 + 6 + 4 + 12 + x}{2} = 18 \\ = 32 + x = 36 \\ x = 36 - 32 = 4 \\ so \: x = 4$