Answer:
Explanation:
Given
Person travel 180 km with [tex]v_1=95\ km/h[/tex]
and slow down to [tex]v_2=65\ km/h[/tex] due to rain
time taken to cover 180 km is
[tex]t_1=\dfrac{180}{95}[/tex]
[tex]t_1=1.89\ hr[/tex]
total time [tex]T=4.5\ hr[/tex]
suppose [tex]t_2[/tex] is the time for which it travels with [tex]v_2=65\ km/h[/tex]
[tex]t_2=T-t_1[/tex]
[tex]t_2=4.5-1.89[/tex]
[tex]t_2=2.61\ hr[/tex]
so distance travel during this time [tex]d_2=v_2\times t_2[/tex]
[tex]d_2=65\times 2.61[/tex]
[tex]d_2=169.65\ km[/tex]
total distance [tex]d=180+d_2[/tex]
[tex]d=180+169.65[/tex]
[tex]d=349.65\ km[/tex]
(b)Average speed
[tex]v_{avg}=\dfrac{Distance}{time}[/tex]
[tex]v_{avg}=\dfrac{349.65}{4.5}[/tex]
[tex]v_{avg}=77.7\ km/h[/tex]
