The sum of the ages of a father and son is \(45\) years. Five years ago, the product of their ages was four times the father's age at that time. The present age of father and son
Answer: C
Let son's age \(=x\) years.
Then father's age\(=(45-x)\) years.
\(\Rightarrow\) \((x-5)(45-x-5) = 4(45- x - 5)\)
\(\Rightarrow\) \((x-5)=4\)
\(\Rightarrow\) \(x=9\)
Their ages are \(36\) years and \(9\) years.