Explanation:
Let running speed = x.
So, cycling speed = 2x.
Total distance traveled = 20 + 25 = 45km
Time taken running = 20/x
Time taken cycling = 25/2c
Total time taken = 5 hours
So, 5 = 20/x + 25/2x
Solving this equation for x gives:
10x = 65. Thus x = 6.5
Since cycling speed = 2x, cycling speed = (6.5)(2)
So cycling speed is 13 km/h.
Hope it helps.