We have to convert the units. 1 mile = 1.60934km, 1 gallon = 3.78541km
Since it's mile per gallon, we divide the units mentioned above.
1 mile / 1 gallon = 1 km / 1 gallon = 1.60934 / 3.78541 = 0.4251
Now multiply this result as a factor to 22
That is 22 * 0.4251 = 9.3522
So the answer is 9.3522