Five years ago mean age of a family was 25 years. What is the present mean age of the family?

Hi Haripriya, I dont know if you have already got this answer...Please see below

Let the number of family members be 'x'
Average age of the family members 5 years ago = 25 years
Therefore, sum of the age of all family members 5 years ago = 25 * x = 25x

Sum of age of these family members now, after 5 years elapsed = 25x + (these added 5 years * no. of family members) = 25x + 5x = 30x

Sum of ages = 30x
no. of family members = x
Therefore, current average age = sum of ages / no. of members = 30x / x = 30

This sum can be answered directly by adding 5 because the number of members did not change during this period...However, if we have to prove it (OR) answer a 3 Mark and above question, we have to do as above
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