.../8=15/...=.../40=35/...=50/80

15/8=15/8 35/40=35/40 50/80

\frac{x}{8}- \frac{15}{x}- \frac{x}{40}- \frac{35}{x}- \frac{50}{80} 
\frac{35}{x}- \frac{50}{80} 
x = \frac{35.80}{50} = 56 
 \frac{x}{40}= \frac{35}{56}
x = \frac{35.40}{56} =25
 \frac{15}{x}= \frac{25}{40} 
x = \frac{15.40}{25} = 24
\frac{x}{8} = \frac{15}{24}
x = \frac{8.15}{24} =5