Question 847452
( km traveled ) / ( km / liter ) = liters consumed
Before servicing engine:
(1) {{{ 400 / ( x/1 ) = 400/x }}} liters consumed
After servicing engine:
(2) {{{ 400 / ( ( x+5 ) / 1 ) = 400/( x+5) }}} liters consumed
The bigger {{{ x }}} is, the greater the fuel efficiency
( less liters / km )