Two towns are 480 km apart. A truck starts from the first town at 6 a.m. at 40 km/h and a car starts from the second town at 8 a.m. at 60 km/h, each heading towards the other. How many hours after 8 a.m. do they meet?

By 8 a.m. the truck has already covered $2\times 40=80$ km, so the gap left is 480 − 80 = 400 km. Moving towards each other they close it at 40 + 60 = 100 km/h, taking 400/100 = 4 hours — they meet at noon. (Dividing the full 480 km by 100 km/h gives 4.8 hours and ignores the truck's two-hour head start.)