Question

Study the bar graph representing the number of persons in various age groups in a town shown in Fig 23.9. Observe the bar graph and answer the following questions:


(i) What is the percentage of the youngest age-group persons over those in the oldest age group?
(ii) What is the total population of the town?
(iii) What is the number of persons in the age-group 60−65?
(iv) What is the number of persons in the age-group 10−15 than in the age group 30−35?
(v) What is the age-group of exactly 1200 persons living in the town?
(vi) What is the total number of persons living in the town in the age 50−55?
(vii) What is the total number of persons living in the town in the age-groups 10−15 and 60−65?
(viii) Whether the population in general increases, decreases of remains constant with the increase in the age-group.

Answer 1

(i) The youngest age group is 10 − 15 years.
Number of persons in the youngest age group = 1400
The oldest age group is 70 − 75 years.
Number of persons in the oldest age group = 300
Difference in the number of people in the youngest age group and oldest age group = 1400 − 300 = 1100
∴ The youngest group has 1100 more people than the oldest group.
∴ % of the youngest group over oldest group
$$\begin{gathered} =\frac{1100}{300}\times 100\% \\ =\frac{1100}{3}\% \\ =366\frac{2}{3}\% \end{gathered}$$

(ii) Total population of the town
= Total number of people from all age groups
= 1400 + 1200 + 1100 + 1000 + 900 + 800 + 300 = 6700

(iii) There are 800 persons in the age group 60 − 65 years.
Explanation: The vertical length of the rectangle against the age group 60 − 65 is up to 800 units.

(iv) Number of persons in the age group 10 − 15 = 1400
Number of persons in the age group 30 − 35 = 1100
∴ Number of more persons in the age group 10 − 15 as compared to that in the age group 30 − 35 = 1400 − 1100 = 300

(v) The age-group of exactly 1200 people living in the town is 20 − 25 years.
Explanation: Looking at the bar graph we can say that the vertical length of the rectangle against the age group 20 − 25 is up to 1200 units.

(vi) The number of people of the age group 50 − 55 years is 900.
Explanation: The vertical length of the rectangle against the age group 50 − 55 years is up to 900 units.

(vii) The number of persons in the age group 10 − 15 years is 1400, and that in the age group 60 − 65 years is 800.
∴ Total number of persons in the age group 10 − 15 years and 60 − 65 years = 1400 + 800 = 2200

(viii) With increase in the age group, the population decreases.
Explanation: As the age group increases, the heights of the rectangles start falling.