## 286. Math Puzzle $3 / 89$

Lydia and Peter are driving with their AG leader to a meeting of model builders in northern Saßnitz from the southern Suhl. They are scheduled to arrive there at 5:00 PM.

The approximately 600 km long route is supposed to be covered with an average speed of 50 km/h, thus taking 12 hours. They start their journey at 5:00 AM.

After a break at 300 km, they notice that they have been driving rather leisurely at only 40 km/h. To arrive on time, they decide to cover the remaining 300 km at a speed of 60 km/h.

Have the clever drivers now correctly maintained their twelve-hour driving time?
Nothing doing, the calculation didn't add up! For the first $300 \mathrm{~km}$, $300: 40=7.5$ hours are required.

The second "ride" consumed $300: 60=5.0$ hours.

In total, the journey was completed in 12.5 hours. The three arrived half an hour late.