Answer:
76.36km
Step-by-step explanation:
Average speed=Total distance covered ÷ Total
time taken
Distance=Time * speed
3*80=240km
2*90=180km
Total distance covered =240+180=420km
Total time taken=3+1/2 an hour+2=5 1/2 hours
Average speed =420km ÷5 1/2 hours
=76.36km/h