working with duration in go

package main

import ("fmt"; "time")

func main() {
	var distance float64 = 10.0
	var speed float64 = 3.0
	
	val := distance / speed * 1000000000
	duration := time.Duration(val)
	
	fmt.Printf("%#v (%T)\n", val, val)
	fmt.Printf("%#v (%T)\n", duration, duration)
	fmt.Printf("%#v (%T)\n", duration.Seconds(), duration.Seconds())
}