Given a MH set up shown below, answer the following.

Problem $1)$ Calculate the slope of the main line between MH $1$ and $2.$

Problem $2)$ compute the invert elevation of the stub for lot $5.$

Problem $3)$ what is the clearance between the $4"$ stub sloping at $4\mathrm{.}0\%$ going to lot $5$ and the gas line. The thickness of the stubs walls are $0\mathrm{.}237"$ and the bottom of the gas line is at $667\mathrm{.}5$