Question

13. In a family of 4 persons an old man joined by increasing the average from 22
years to 30 years, then the age of old man is:
O 52 years
O 62 years
O 70 years
O 82 years​

Answer 1

Answer:

Avg of 4 people = 22

Avg of 5 people including the old man = 30

let age of old man be x

Let sum of 4 people's age be y

Average age = sum of all ages / total members

so

Average of 4 people = 22

y/4 = 22

y = 88

so avg of 5 people = y +x/5

30 = 88 + x/5

150 = 88 + x

x = 62 yrs

option 2 is correct

Hope It Helps ^_^