1 hour = 60 minutes
Divide by 2 because of the jump from 60 minutes to 30 minutes.
If you travel for half of the time, then you travel half the original distance.
This of course only works if the speed is kept the same.
So that's how we go from 50 km to 25 km.
Here's another approach using a proportion.
(50 km)/(1 hour) = (x km)/(30 min)
(50 km)/(60 min) = (x km)/(30 min)
50/60 = x/30
5/6 = x/30
5*30 = 6x
150 = 6x
x = 150/6
x = 25
Another method:
distance = rate*time
distance = (50 km per hour)*(1/2 hour)
distance = 25 km
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