Answer:
Jon's aunt age would be 52 years.
Step-by-step explanation:
Her aunt's age= 23+ the eldest child's age
Age of the eldest child= 17+3= 20, 20+3=23, 23+3=26 and the age of the the eldest child would be 26+3 i.e. 29
So, Jon's aunt would be 52 years old.