Ok so a compass, is a technical drawing instrument that can be used for inscribing circles or arcs. Compasses can be used for drafting, navigation and graphing.
The answer is 12. I am 1,000,000% positive that it is the correct answer
The answer for this problem: Option C.
Girls: 81
boys: 75
4x +6 = 156
4x = 150
x = 37.5
2x = 75
girls: 75 + 6
boys: x