Answer
speed of cyclist = 12.8 km/h
speed of walker = 4.8km/h
The distance the cyclist traveled = 8km
A walker traveled = 3km
Let the speed of the work be x
The speed of the cyclist is 8 km/h more than the speed of the walker
Speed of the cyclist = (x + 8) km/h
Speed = distance / time
Cross multiply
Distance = speed x time
time = distance / speed
For the cyclist
Time = 8 / (x + 8) ---------- equation 1
For walker
time = 3 / x
Since, they both traveled at the same time
Equate the two equations together
8x = 3x + 24
Collect the like terms
8x - 3x = 24
5x = 24
Divide both sides by 5
5x/5 = 24/5
x = 4.8 km/h
The speed of the walker is 4.8 km/h
Speed of the cyclist = x + 8
Since x = 4.8
Speed of the cyclist = 4.8 + 8
Speed of the cyclist = 12.8 km/h