can you help me with this math probelm for Algebra 2?

Paige and Marry are planning a trio to the mountains. For the first part of their trip, they travel at an average rate of 52 mph, and on the second part of the trip, which takes half as much time as the first part, they traveled at an average rate of 35mph. If the odometer shows that they travel a distance of 104.25 miles to the mountains, how long did they travel at each rate? okay so the teacher gave me the answers....1.50 and 3/4 (three fourths) .. I tried for nearly and hour to get it but I just cant can someone help me please? it will really mean a lot!:)