Answer:
4 km/hr
Explanation:
Dina and Masha started out on a 10 km bike path at the same time.
Distance = 10 km
Dina’s biking speed was 5 km/h
Time taken by Dina is Distance / speed
So

Time taken by Dina is 2 hours
Same time is taken by Masha but 2 km left
So distance covered by Masha in 2 hours is 10-2 = 8 km
We know speed = distance / time

Masha’s biking speed= 4km/hr