swift-average-speed

let milesToKmRation = 1.60934
let distance = 371.0
let duration = 2.3

func kilometersToMiles(kilometers: Double) -> Double {
    return kilometers / milesToKmRation
}

func milesToKilometers(miles: Double) -> Double {
    return miles * milesToKmRation
}

func calculateAverageSpeed(distance: Double, durationInHours: Double) -> Double {
    return distance / durationInHours
}

let averageSpeed = calculateAverageSpeed(distance: distance, durationInHours: duration)
let tripInMiles = kilometersToMiles(kilometers: distance)
let averageSpeedInMeters = averageSpeed * 1000 / 3601

let averageSpeedInMiles = calculateAverageSpeed(distance: tripInMiles, durationInHours: duration)

print(String(format: "Average speed in km/h %0.2f", averageSpeed))
print(String(format: "Average speed in mph %0.2f", averageSpeedInMiles))
print(String(format: "Average speed in m/s: %0.2f", averageSpeedInMeters))