a man is 9 years older than his brother, if the product of their ages is divided by the sum of their ages, the answer is 20. find their ages
Mathematics · College · Mon Jan 18 2021
llm
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Let brother's age be x yrs
Then, his age is (x + 9) yrs
According to question,
x(x + 9)/(x + x + 9) = 20
(x² + 9x)/2x + 9 = 20
Cross-Multiplying, we get
x² + 9x = 40x + 180
x² - 40x + 9x - 180 = 0
x² - 31x - 180 = 0
x² - 36x + 5x - 180 = 0
x(x - 36) + 5(x-36) = 0
(x + 5) (x-36) = 0
Since, x = -5 is not possible
x = 36 (brother's age)
And, his age = 36 + 9 = 45