If I travelled 5km/h slower than the average speed, which is 81.29 km/h by how much would this increase my total driving time?

Answer 1

81.29 kmh decreased by 5kmh =

81.29-5 = 76.29 kmh

You used to drive 81.29 km in one hour

Now it will take you one hour to go 76.29 km and the additional 5 km will take another 5/76.29th of an hour= about 3 minutes and 56 seconds

total driving time that used to take 1 hour now takes 1 hour and almost 4 minutes. You're running 4 minutes later than usual by slowing down 5 kmh. if you plan on going 81.26 km