Answer:
80 km/hr
Step-by-step explanation:
0.5 hour = 30 min
40 km in 30 min
80km in 60 min
-x - 6 > 21 - 28x
27x - 6 > 21
27x > 27
x > 1
For the first one 25.925%
The second is 23.333%
The third is 27.27%
Let me know if this helps!