Answer:
Option D - 30 years
Step-by-step explanation:
Given : Michelle is three times as old as Fiona. Fiona is twice as old as Madeline. Madeline is five years old.
To find : How old is Michelle?
Solution :
Let the Michelle is x years old.
The Fiona is y years old.
The Madeline is z years old.
According to question,
Madeline is five years old.
i.e. z=5
Fiona is twice as old as Madeline.
i.e. ![y=2z](https://tex.z-dn.net/?f=y%3D2z)
![y=2(5)](https://tex.z-dn.net/?f=y%3D2%285%29)
![y=10](https://tex.z-dn.net/?f=y%3D10)
Fiona is 10 years old.
Michelle is three times as old as Fiona.
i.e. ![x=3y](https://tex.z-dn.net/?f=x%3D3y)
![x=3(10)](https://tex.z-dn.net/?f=x%3D3%2810%29)
![x=30](https://tex.z-dn.net/?f=x%3D30)
Michelle is 30 years old.
Therefore, Option D - 30 years old is correct.