To find compound probability, multiply the probability of the first and second events. In this case, if you wanted to draw the green first and then the blue, 10/24 or 5/8 times 6/23 equals 30/184 which reduces to 15/92.
52 kilometers in 4 hours = 52 x 4 = 208 km in 4 hours
Total of 5 hours = 208 km + 62 km = 270 km
Average speed = 270 km / 5 hours = 54 km per hour
Answer
54 km per hour