Answer:
57.78 km/hr
Explanation:
Total time taken, t = 6 hours
Total distance covered, d = 520 km
Distance by car = 260
Distance by train = 520 - 260 = 260 km
Train speed = x
Car speed = 2x
Average speed speed = 3x /2
Speed = distance / time
1.5x = 520 / 6
9x = 520
x = 520 / 9
x = 57.777
Average speed of train = 57.78 km/hr