Question
The average age of a man and his son is 40 years. The
ratio of their ages is 11 : 5 respectively. What is the son's age?Solution
Total age = Average age × number of people Total age of man and his son = 40 × 2 ⇒ 80 years Ratio of their ages = 11 : 5 Let the ratio of age of man and son be 11x : 5x ⇒ 11x + 5x = 80 ⇒ x = 5 years Age of son = 5x ⇒ 5 × 5 ⇒ 25 years ∴ The son's age is 25 years.
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