Maria Petrovna is walking down the road at a speed of 4 km/h. Seeing a stump, she sits on it and rests for the same whole number of minutes. Mikhail Potapovich is walking down the same road at a speed of 5 km/h, but sits on each stump twice as long as Maria Petrovna. They both set out and arrived at the same time. The length of the road is 11 km. How many stumps could there be on the road?