Pelden drives an average of 30km/h for r hours and an average of 20 km/h for the remaining 5 hours. He travels a total of 51 km

i) Write an equation to model this situation

ii) Write a function that tells you how many hours he travels at 30km/h if you know how many hours he travels at 20km/h

iii)How long does he travel at 30km/h if he travels 1.2h at 20km/h? ​