Answer: The age of the twins is 10 years.
Step-by-step explanation:
Suppose the age of older sister be x
Let the age of twins sister be x-9, as they are born after 9 years.
Product of their ages be

Sum of their ages will be

According to question,

So, Age of older sister will be 19 years.
Age of the twins will be

Hence, the age of the twins is 10 years.