Question

A fast Humvee drove from Desert A to Desert B. for the first 12 hours and traveled at an average speed of 185 km/h. For the next 13 hours, it travelled at an average speed of 160 km/h. What was the average speed of the whole journey?

Answer 1

Answer:

The value is $v_t = 172 \ km/h$

Explanation:

From the question we are told that

    The average speed for the first 12 hours is $u = 185 km/h$

    The average speed for the next 13 hours is  $v = 160 \ km/h$

   

Generally the total time taken is mathematically represented as

     $t_t = 12 + 13$

=> $t_t = 25 \ h$

The distance covered in the first movement is

          $D = u * 12$

         $D = 185 * 12$

        $D = 2220 \ km$

The distance covered in the first movement is

          $d= v * 13$

         $d = 160 * 13$

        $d = 2080 \ km$

The total distance traveled is  

       $D_t = D + d$

       $D_t = 2220 +2080$

      $D_t = 4300 \ km$

The average  of the whole journey is

      $v_t = \frac{D_t}{t_t}$

     $v_t = \frac{4300}{25}$

     $v_t = \frac{4300}{25}$

    $v_t = 172 \ km/h$