Ahmed spent 2/3 of his money on a burrito and a water. the burrito coast 2 times as much as the water. the burrito cost $4, how much money does ahmed have left?

If a burritto is twice as much as water the the water is two dollars. if Ahmed spent 2/3 of his money then( 4+2=6) for burrito and water it means he had nine dollars originally so he is left with 3 dollars.  

4+2=-2. 1+2=3. y=-2/3x+b. 2=4/3+b. 2/3=b. the answer is y= -2/3x+2/3