$[5$ pts$]$ a$)$ Use the Christensen method discussed in class to calculate the lower heating value $($LHV$,$ in $M\frac{J}{M}T)$ of a waste that has a moisture content of $28\%$ and the following elemental content: $25\%C,10\%H,20\%O,1\%N,0\mathrm{.}5\%S,$ and $18\mathrm{.}5\%$ ash. b$)$ Use the method from the Christensen reading to calculate the higher heating value of the waste from the LHV that you calculate in part $($a$).$