Question

a body moves on to 120 km long track if he moves first 30 km with a speed of 30 km per hour then what is the speed for next 90 so that average speed becomes 60 km per hour​

Answer 1

Answer:

90 km/hr

Explanation:

AVERAGE is 60 km/hr  so   120 km / 60 km/hr = 2 hours total

first 30 km / 30 km / hr = 1 hour   used    1 hour left

  now there is 90 km to cover in the second hour

         so that must be   90 km/hr