With this one, you can do a method of guess and check. Find a number that's logical, like 70. multiply 70 by 6, which gives you 420. The remainder of the 117 would be non-students,117-70=47. You take that 47 and multiply that by 12, which gives you 564. 564+420=984. So, that probably means we should go down from the 70. Try 65. 65×6=390. 117-65=52. 52×12=624. 624+390=1014. That means we went back too much. Let's try right in the middle, at 67. 67×6=402. 117-67=50. 50×12=600. 600+402=1002! So, with that being said, the answer would be 67!
