Respuesta :

ojasvijamkar

3x+x=36

4x=36

x=36/4

x=9

Mandela's sister's age = x = 9

Mandela's age = 3x = 3×9 = 27

Answer:

Her sister is 9 years old and

Mandela is 27 year old.

Step-by-step explanation:

Sister = x = 9

Mandela = 3x = 3(9) 27

x + 3x = 36

4x = 36

x = 36/4

x = 9