I have no idea what "dependence of speed to time" means. It is not a complete sentence- there is no verb.
And I cannot read the language in your link. Since it says "a= v/t" and, further has a "7", "10 k/h", and "10/7". I might guess they are saying that the (average) acceleration in increasing speed by 10 k/h in 7 hours is 10/7 k per hour^2. You could also say that if you accelerate at 10/7 km per hour per hour for 7 hours, you speed will have increases by 10 km per hour (v= at).