9 years ago, the average age of a family of five members was 33 years. Now, three new members join whose ages are in ascending order with consecutive gaps of 8 years. If the present average age of the family is the same as it was 9 years ago, what is the age (in years) of the youngest new member?
9 years ago, the average age of a family of five members was 33 years. Now, three new members join whose ages are in ascending order with consecutive gaps of 8 years. If the present average age of the family is the same as it was 9 years ago, what is the age (in years) of the youngest new member? Correct Answer 10
The age of the family 9 years ago = 5 × 33 = 165
The age of the family at present = 165 + 5 × 9 = 210
Let the ages of three new members of the family are a, (a + 8) and (a + 16).
According to the question,
Present average age of the family = 33
⇒ /8 = 33
⇒ 210 + 3a + 24 = 264
⇒ 3a = 30
⇒ a = 10 years.
∴ the age of the youngest member = 10 years.
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Feb 20, 2025