Doreen and Irena plan to leave their houses at the same time, roller blade towards each other, and meet for lunch after 2 hours on the road. Doreen can maintain a speed of 3.5 miles per hour, which is 70% of Irena's speed. If they meet exactly as planned, what is the distance between their houses?
◦ 7 miles
◦ 17 miles
◦ 10 miles
◦ 11.9 miles