The time needed for the car to go from 0 to 100 miles per hour varies inversely with the car's horsepower. At 200 horsepower the car can go from 0 to 100 mph in 12 secounds. How long should the car take if he can increase the horsepower to 240hp?

I agree with John. But when your car stalled while driving you do not have time for making such calculations. Have you ever had this situation in your life? Why do not we teach our kids about it? There should be a class called «life education» at school. I would tell them to read more about it and choose the best lithium ion jump starter to avoid wasting time waiting for help.