Respuesta :

12 Km / hour

using the formula

average speed = [tex]\frac{distance}{time}[/tex] ( where time is in hours )

40 min = [tex]\frac{40}{60}[/tex] = [tex]\frac{2}{3}[/tex] hour

speed = 8 ÷ [tex]\frac{2}{3}[/tex] = 8 × [tex]\frac{3}{2}[/tex] = 12 Km / hour


Answer:

Average bus speed = 12 kmph

Step-by-step explanation:

Distance from her grandparents house = 8 km

[tex]\texttt{Time Sara took to travel = 40 min}=\frac{40}{60}=0.667hours[/tex]

We have

          Distance traveled = Average speed x Time taken

           [tex]\texttt{Average speed}=\frac{\texttt{Distance traveled}}{\texttt{Time taken}}\\\\\texttt{Average speed}=\frac{8}{0.667}=12kmph[/tex]

Average bus speed = 12 kmph