From consecutive aerial photos of traffic along a highway, one observes that there are ten cars per kilometer with 0 velocity (they are parked), forty cars per kilometer traveling at 15 km/hr and twenty cars per kilometer traveling at 30 km/hr. Determine the space mean speed of traffic and the time mean speed

The space mean speed is  

The Time mean speed  is    

Explanation:

    From the question we can derive that

             Velocity (Km / h)(V)    0()            15()         30()

                 No of Cars(N)        10()           40 ()       20()

 From the table above the space mean speed would be

  From the table above the Time mean speed would be

We did not make use of because the speed was zero

the answer is 3.1 his answer is wrong mines is right

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.