Q$1.$ A four$-$cylinder engine is used in a small truck has been converted to run on propane fuel. During the seasonal test, the dry analysis of the engine exhaust gives the following volumetric fraction:

$,C{O}_2,CO,O_2$

$x_i,4\mathrm{.}9\%,9\mathrm{.}79\%,2\mathrm{.}54\%$

Calculate the equivalence ratio at which the engine is operating