Driving Licence Book (19th Edition, page 84)

"If you increase your average speed by 10 km/h, the time gain per 10 km will be: approximately 1 minute at speeds under 90 km/h and, approximately 0.5 minute at speeds over 90 km/h"

Following Calculations

Method 1

Original speed = 100 km/h New speed = 110 km/h Minutes per hour = 60 minutes Number of kilometres = 10 km Calculate first how many minutes it takes to travel 1 km at both speeds: 60 / 100 = it takes 0.6 minutes to travel 1 km 60 / 110 = it takes 0.54 minutes to travel 1 km Answer: As a result, the greater speed takes slightly less time. The difference is as follows: 0.6 - 0.54 = 0.06 minutes faster per 1 km 0.06 * 10 = 0.6 minutes time gain per 10 km 0.6 * 60 = 36 seconds (Convert to seconds to understand better)

Method 2

Original speed = 100 km/h New speed = 110 km/h 10 km = 10,000 metres Fixed conversion rate km/h to m/s = 3.6 times Distance / speed = time For the formula to work requires us to use metres instead of 10 km and we need to use metres per second (m/s) instead of kilometres an hour (km/h). The speeds are therefore recalculated to m/s: 100 / 3.6 = 27.78 m/s 110 / 3.6 = 30.56 m/s Distance / speed = time: 10,000 / 27.78 = 360 s 10,000 / 30.56 = 327 s 360 - 327 = 33 seconds