Citizen E610 Instruction Manual page 96

[Calculation of fuel consumption rate (consumed per hour)]
Q : If the drive time is 5 hours and 30 liters fuel are consumed, what is the fuel
consumption rate ( liters/hour) ?
A : Align 30 of the outer scale with 5:00 of the inner scale.
Result: 6 Liters per hour - 60 is indicated on the SPEED INDEX "  "
corresponding to the outer scale.
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