Super confused... Please Hlp

[ALevy]

Aragorn the Great has boasted to his hordes of followers that many notorious villain has fallen to his awesome sword: His total of 560 victims consists of evil sorcerers, trolls, and orcs. These he has slain with a total of 620 mighty thrusts of his sword; evil sorcerers and trolls each requiring two thrusts and orcs each requiring one. He has slain trolls five times as much as sorcerers. How many of each villain has he slain?

 

[Denis]

HINT:
Let a = evil sorcerers, b = trolls, and c = orcs.
a + b + c = 560 [1]
2(a + b) + c = 620 [2]
5a = b [3]

Take over...