Question

the average age of 5 members of a family is 21 years, if the age of grandfather is included. The average age is increases by 9 year. what is the age of grandfather. Explain with steps

Answer 1

Step-by-step explanation:

Sum of 5 members= 21×5

=105 years

Sum of 6 members=6×30

=180

now age of grandfather=180-105

=75 years

Answer 2

Answer:

Age of grandfather is 75 years.

Step-by-step explanation:

Average age of five members = 21

⇒ Let the ages of the five members be a, b, c, x, y,

Then,

a+b+c+x+y/5 = 21

a+b+c+x+y    = 21 × 5 = 105

∴ Sum of ages of family members is 105.

Let grandfather's age be q.

If his age is added, then,

105 + q / 6 = 21 + 9 = 30

105 + q      = 30 × 6 = 180

q = 180 - 105

q = 75