The son is 8. I’m not sure if I’m right hope this helps
The answer is 600 because 1 out 3 is 60 so to find the bag multiply by two while to find 1 out 5 of her monet take 60 times 3 which is 180. 180 times 4 is the money she spent on her mobile phone so take the money spent on her mobile phone(720)minus the amount of money spent on the bag(120)
There's a website called desmos.com. That website can tell you the answer