Quantity[19.25,"Kilometers"]+Quantity[13,"Miles"]

Quantity[20,"Feet"]/Quantity[2.3,"Seconds"]+Quantity[9,"Meters"/"Seconds"]

N[Quantity[175, "Pounds"]/Quantity[100, "Kilograms"]]

Quantity[24,"Miles"/"Gallons"]*Quantity[16.2,"Gallons"/IndependentUnit["tank"]]*Quantity[1/8,IndependentUnit["tank"]]