The ratio of the father's age to his son's age is $7:3$. The product of their ages is $756$. The ratio of their ages after $6$ years will be:

If $a-b : b-c : c-d = 1 : 2 : 3$,then what is the value of $(a+d) : c$?

In a school,there were $1554$ students and the ratio of the number of boys to girls was $4:3$. After a few days,$30$ girls joined the school but some boys left; as a result,the ratio of boys to girls became $7:6$. The number of boys who left the school is:

The present ages of three persons are in the ratio $4: 7: 9$. Eight years ago,the sum of their ages was $56$. Find their present ages (in $years$).

Arti has coins of the denomination of $Rs. 1$,$50 \text{ paise}$,and $25 \text{ paise}$ in the ratio of $12: 10: 7$. The total worth of the coins she has is $Rs. 75$. Find the number of $25 \text{ paise}$ coins.

At present,Kavita is twice Sarita's age. $8 \ yr$ hence,the respective ratio between Kavita's and Sarita's ages will be $22:13$. What is Kavita's present age (in $yr$)?