# The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is ₹ 18. Find the missing frequency f.

**Solution:**

To solve this question, we will use assumed mean method.

Mean, (x) = a + Σf_{i}d_{i}/ Σf_{i}

We know that, class mark, x_{i} = (Upper class limit + Lower class limit)/2

Taking assumed mean, a = 18

From the table, we obtain.

Σf_{i} = 40 + f

Σf_{i}d_{i} = 2 f - 40

Mean, (x) = a + Σf_{i}d_{i}/Σf_{i}

18 = 18 + [(- 40 + 2f)/(40 + 2f)]

18 - 18 = (2 f - 40)/(40 + f)

2 f - 40 = 0

f = 20

Thus, for the given problem the missing frequency f is 20.

**Video Solution:**

## The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is ₹ 18. Find the missing frequency f

### NCERT Solutions for Class 10 Maths - Chapter 14 Exercise 14.1 Question 3:

The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is ₹ 18. Find the missing frequency f

The missing frequency f for the given distribution showing the daily pocket allowance of children of a locality is 20.