Answer:
My age is 13 years, my brother's age - 16 years, my sister's age is 11 years, my mom's age - 47 years.
Explanation:
Let x be my age.
I am 3 years younger than my brother, then my brother is (x+3) years old.
I am 2 years older than my sister, then my sister is (x-2) years old.
My mom's age is one less than three times my brother's age, then my mom's age is 3(x+3)-1.
When you add all our ages you get 87, then the equation that represents this situation is

Simplify this equation:

My age is 13 years, my brother's age - 16 years, my sister's age is 11 years, my mom's age - 47 years.