[tex]a+b+c=198 \\ \\ b= \frac{a}{4} + 12= \frac{a+48}{4} \\ \\ c= \frac{b}{2} + 15 = \frac{b+30}{2} = \frac{ \frac{a+48}{4} + 30 }{2} \\ \\ c= \frac{a+168}{4} \times \frac{1}{2} = \frac{a+168}{8} \\ \\ a+b+c=198 \\ a+ \frac{a+48}{4} + \frac{a+168}{8} = 198 /*8 \\ 8a+2a+96+a+168=1584 \\ 11a+264=1584 \\ 11a=1320 \\ \boxed{a=120} \\ \\ b= \frac{a+48}{4} \\ b= \frac{168}{4} \\ \boxed{b=42} \\ \\ c= \frac{b+30}{2} \\ c= \frac{72}{2} \\ \boxed{c=36}[/tex]
