Joe has $19 more than Erin, Shelly has twice as much as Erin; Colin has $6 less than Erin has. In total, the students have $68. How much money does each separate student have?

E = Erin

E + E + 19 + 2E + E - 6 = 68

5E + 13 = 68

5E = 55

E = 11

Take it from there.