Question

Number of people of different age groups staying in a hotel is shown in the histogram given below?

What is the total number of people having age less than 30?

• A. 20
• B. 25
• C. 15
• D. 5

Answer 1

The correct option is B 25

Class length is varying in the given histrogram.

Modified length = $\frac{\text{Frequency of the class}}{\text{Length of that class}}\times \text{Least Class length}$

The total number of people having age less than 30 = People in age group (0-20) and people in age group (21-30).

In case of class interval 0-20:-

Modified length = Length of red bar = 5
Class length = 20-0 = 20
Least class length = 40-30 = 10

5= $\frac{Frequency}{20}\times 10$

$⟹Frequency=10$

In case of class interval 21-30, class length is least, so we can directly take the length of the bar.

$⟹Frequency=15$


The total number of people having age less than 30 = 10 + 15 = 25.