Answer: Running speed is 10k/h
Biking speed is 50k/h
Explanation:
My procedure may be unconventional, but it works:
Compute the time it takes, then translate to speed. 25k at biking speed takes 2 hours less than at running speed which is 1/5 bike speed.
Distance/speed = time 25/x=25/(5x-2) cross multiply divisors
25(5x-2) = 25x ==> 125x -50 =25x ==> 100x = 50
x = 0.5 hours at biking speed 25k/0.5h = 50k/h
Running speed = 50/5 10k/h
Proof: 25k/ 10k/h = 2.5 hours
25k /50k/h = 0.5 hours
2.5 h - .5 h = 2 hours, the difference stated in the question.