Groundwater was contaminated by a spill, and benzene and vinyl chloride remain in the water, each at a concentration of 2.0 mg/L. The groundwater is used as a potable water supply for a town of 75,000 people. Calculate the LADD for a male who weighs 80 kg and who lives in this town for 70 years, and drinks only the groundwater with no removal of these chemicals.

For cyclohexane compounds drawn in a chair conformation:   -axial bonds are vertical  -equatorial bonds are parallel to two bonds within the ring.  thus, as i assume the chair conformation is drawn:   -the x group is in an axial position, as are the five other vertical bonds.  -three axial bonds are on the top face of the ring  -the other three axial bonds are on the bottom face  the position of the second substituent on each ring carbon is equatorial.  gauche groups must be on an adjacent carbon such as carbon 6 and carbon 2, and also gauche groups are rotated by 60 degrees relative to each other.  drawing the newman projections for c1–c2 and c1–c6 aids in visualizing the groups that are gauche to the y group on c1.  click this link and watch some academic videos that may you more understand the topic 

Ithinks its false. tell me if im wrong

The answer is 65.3312