var minimum = 10.0;
var maximum = 20.0;

function Update() {
    transform.position = Vector3(Mathf.SmoothStep(minimum, maximum, Time.time), 0, 0);
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public float minimum = 10.0F;
    public float maximum = 20.0F;
    void Update() {
        transform.position = new Vector3(Mathf.SmoothStep(minimum, maximum, Time.time), 0, 0);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public minimum as single = 10.0F

    public maximum as single = 20.0F

    def Update():
        transform.position = Vector3(Mathf.SmoothStep(minimum, maximum, Time.time), 0, 0)