Question

Davit and Mila are both travelling by train.

Answer 1

The difference between the average speed in km/h of their trains are 53.538 km/h.

Step-by-step explanation:

        The given is,

             Davit's train travels 90 km in 50 minutes.

             Mila's train travels 210 km. It leaves at 12:05 and arrives 13:35.

Step:1

             From the given,

              Time required to milas train travels 210 km

                             = 12:05 - 13:35

                             = 1.30 hours

Step:2

            Time to Davit's train travels 90 km is need to convert in hours from minutes,

                    =  50 minutes

                    = $\frac{50}{60}$ hours

                    = 0.833 hours

Step:3

        Average rate of Davits train,

                    = $\frac{Distance traveled}{Time taken}$

                    = $\frac{90}{0.833}$

                    = 108 km/h

Step:4

      Average rate of Mila's train,

                   = $\frac{Distance traveled}{Time taken}$

                   = $\frac{210}{1.30}$

                  = 161.538 km/h

Step:5

       The difference between the average speed of the both trains in km/h,

                = 161.538 - 108

                = 53.538 km/h

Result:

     The difference between, the average speed of their trains are 53.538 km/h.