Brianne is three times as old as Camila. Four years from now she will be two-times as old as Camila. How old are Brianne and Camila now?

B=brianne present age

c=camila present age

b=3c (brianne is three times as old as camila)

b+4=2 (c+4) (four years from now she will be two times as old as Camila)

b + 4 = 2c + 8

b = 2c + 8 - 4

b = 2c + 4

Replace b with 3c

3c = 2c + 4

3c - 2c = 4

c = 4

Camila is four years old.

b+4=2c+8

b=2 (4) + 4

b=8+4

b=12

Brianne is 12 years old.