Shari and Ana are playing games at an arcade. Shari has $37.50 and is playing $0.50 games. Ana has $42.75 and is playing $0.75 games. Sandor wants to know when Shari and Ana will have the same amount of money remaining. So he wrote and solved this equation. Let x = number of games played. Equation: 37.50 – .5x = 42.75 – .75x Step 1: 37.50 – 1.25x = 42.75 Step 2: – 1.25x = 5.25 Step 3: – 4.2 = x Sandor knows his answer is incorrect because a negative number of games cannot be played. What was Sandor’s mistake? The variable x should represent the amount of money left. The equation should have sums on both sides. In step 1, he should have added .75x to both sides. In step 3, he should have added 1.25x to both sides.