Question

I am the eldest child of my parents. There is a gap of 6 years between the ages of my brother and sister including myself. If my mother was 22 years, when I was born, what was age at the birth of her youngest child.

Answer 1

There are two sisters and one brother in the family.  

So, the age of brother is B and sisters is S1 and S2.

B-S1= 6-------1

S2- B= 6---------2

Adding 1 and 2 we get,  

B-B+S1-S2=6-6

S2-S1=0

S2=S1.  

This means the sisters are twins and the brother is 6 years younger to the sisters.  

Thus, the mother’s age was 22-6=16 years.