Question

In a big joint family of 42 people the difference between the ages of great grandfather and great grandson is hundred years leaving these two members out the average age of remaining members is 28 years the average age of the family otherwise is 30 years find the age of the great grandfather

Answer 1

Answer:120

Step-by-step explanation:

Sum of family ages without those two persons is 28*40= 1120

Sum of family ages with these two persons is 30*42 = 1260

So the sum of ages of these two persons is 1260-1120= 140 years

So the sum of two ages is 140 and the difference is 100 so the ages ate 120 and 20

Answer 2

Answer:

120

Step-by-step explanation:

avg of 42 persons=30

avg of 40 persons=28

age of two persons=(42*30-40*28)

=140

ie, sum of ages =140

diff of ages =100(already given )

take x as age of grand father and y as age of grand son,

x+y=140 (1)

x-y=100 (2)

------------------ add (1) and (2)

2x=240

x=120., y=20