A40/8 m/sB500/9 m/sC188/9 m/sD270/8 m/sAnswer: B. 500/9 m/s Read Explanation: aerage speed =(total distance )/(total time)distance =12800-12000=800kmtime = 4hrsspeed =800/4=200 kmphspeed in m/s =200*{5/18}=500/9 m/s Read more in App