Answer:
67.89%
Explanation:
Energy Efficiency=[tex]\frac {U_{energy}}{T_{energy}}\times 100[/tex]
Where [tex]U_{energy}[/tex] is useful energy and [tex]T_{energy}[/tex] is the total energy
The useful energy= (19-5-1.1) million= 12.9 million
The total energy= 19 million
[tex]Efficiency=\frac {12.9}{19}\times 100=67.89473684\approx 67.89[/tex]
Therefore, the efficiency of the boiler is 67.89%