Nurse mathematics

Question

Edward has $400 more than Robert. After Edward spends $60 on groceries, he has 3 times more money than Robert. How much money does Robert have?

Answer 1

Robert money= x

Edwards money =y

x+400=y

y-60=3x

x=y-400

y-60=3(y-400)

y-60=3y-1200

1140=2y

y=570

x=570-400=170