since we have two variable, then we need two equations:
first equation:
B lies on AC, therefore
AB+BC=AC
3x+2y+16=60
3x+2y=44 .......> equation I
second equation:
B is the midpoint of AC, therefore
AB=BC
3x=2y+16 ......> equation II
substitute wit II in I:
2y+16+2y=44
4y=28
y=7
substitute in II to gey x:
3x=2(7)+16
3x=30
x=10