Explanation

Total age of 5 members = 5 x 21 = 105

Average of 6 members = 21 + 9 = 30

Total age of 6 members = 6 x 30 = 180

Age of grandfather = 180 - 105 = 75 years

Explanation

To find the Arithmetic Mean (Average):

Add the numbers: 10 + 20 + 30 + 40 + 50 = 150

Count the numbers: 5

Divide the sum by the count: 150/5 = 30

Last verified on 23-10-2026

Explanation

Every year population increase = 700

after five year population increase = 5 x 700= 3500

So intial population = 25000-3500=21500

 Last updated on 12 NOV 2026

Explanation

Total students = 26

Students who like football = 21

Students who like cricket = 14

Let x be the number of students who like both football and cricket.

Using the formula:

(Football ∪ Cricket) = Football + Cricket – Both

So,

26 = 21 + 14 – x

26 = 35 – x

x = 35 – 26

x = 9

 Last updated on 12 NOV 2026

Explanation

To find the percentage of girls, you need to divide the number of girls (28) by the total number of students (20 boys + 28 girls = 48) and multiply by 100:

(28 ÷ 48) x 100 = 58.3%

So, the percentage of girls in the class is 58.3%.