Respuesta :

Hey there! :D

f= 4x+x 

Where f is their total ages, and x is Robin's age. Batman's age is 4 times Robin's. 

Plug in what you know. 

45=4x+x

45=5x

x=9 

Robin is 9. 

9*4= 36

Batman is 36.

I hope this helps!
~kaikers

Answer:

Robin is 9 years old and Batman is 36 years old

Step-by-step explanation:

Batman: 4x

Robin: x

4x + x = 45

5x = 45

x= 9