[tex] \frac{ \frac{x}{2} + \frac{x}{3} + \frac{x}{4} + \frac{x}{6} }{4} = 45 \: | \times 4[/tex]
[tex] \frac{x}{2} + \frac{x}{3} + \frac{x}{4} + \frac{x}{6} = 180 \: | \times 12[/tex]
[tex]6x + 4x + 3x + 2x =2160 [/tex]
[tex]15x = 2160 \: | \div 15[/tex]
[tex]x =144 [/tex]
