Question

1p

Answer 1

Answer:

O 81 km per hour

Explanation

Given parameters:

Number of days traveled  = 3 days

Distance covered on the first day  = 1080km

Time of travel  = 10hrs

Rate of travel  = 108km/hr

Time of travel on second day = 12hrs

Rate of travel  = 90km/hr

Time of travel on third day  = 18hrs

Rate of travel  = 60km/hr

Unknown

Average speed  = ?

To find the average speed, we sum the distances and divide by the sum of the time.

  Average speed  = $\frac{Total distance}{total time}$

we do not know the second and third distances;

  Distance  = speed x time

D2  = 90 x 12 = 1080km

D3  = 60 x 18  = 1080km

    Now;

  Average speed  = $\frac{1080 + 1080 + 1080 }{10 + 12 + 18 }$

 

 Average speed  = $\frac{3240}{40}$   = 81km/hr

The average speed is 81km/hr