The sum of the ages of a father and son is $45$ years. $5$ years ago,the product of their ages was four times the father's age at that time. The present age of the father is (in years):

Radha's present age is $3 \text{ years}$ less than twice her age $12 \text{ years}$ ago. Also,the ratio of Raj's present age to Radha's present age is $4:9$. What will be Raj's age after $5 \text{ years}$? (in $\text{years}$)

Raman's present age is three times his daughter's and $9/13$ of his mother's present age. The sum of the present ages of all three of them is $125 \text{ years}$. What is the difference between the present ages of Raman's daughter and Raman's mother? (in $\text{years}$)

$A$ father is now $3$ times as old as his son. $5$ years back,he was $4$ times as old as his son. The age of the son is:

After replacing an old member by a new member,it was found that the average age of five members of a club is the same as it was $3$ years ago. The difference between the ages of the replaced and the new member is (in years):

Eighteen $years$ ago,a father was three times as old as his son. Now the father is only twice as old as his son. Then the sum of the present ages of the son and the father is