সব প্রশ্নে ফিরে যান
Math
A car covers four successive 7 km distance at speeds of 10 km/hr, 20 km/hr, 30 km/hr and 60 km/hr , respectively . Its average speed over this distance is :
A) 40 km/hr
B) 30 km /hr
C) 20 km/hr
সঠিক উত্তর
D) 50 km/hr