Given:
Able's age can be represented by x.
Able's sister is 4 years younger than him.
Able's older brother is twice as old as he is.
The combined age of all three siblings is 32.
To find:
The age of Able's younger sister.
Solution:
Able's age can be represented by x.
Able's sister is 4 years younger than him.
Age of Able's sister = (x-4)
Able's older brother is twice as old as he is.
Age of Able's older brother = 2x
The combined age of all three siblings is 32.


Add 4 on both sides.


Divide both sides by 4.


The age of Able is 9 years. So, age of his younger sister is

Therefore, the age of Able's sister is 5 years.