Answer:
31.182 seconds
Explanation:
s = Distance
Velocity = Distance/Time
Velocity of person is
[tex]v=\frac{s}{48}[/tex]
Velocity of sidewalk is
[tex]v_s=\frac{s}{89}[/tex]
When the person is walking along the direction of the sidewalk the combined velocity will be
[tex]v_c=v+v_s=\dfrac{s}{48}+\dfrac{s}{89}\\\Rightarrow v_c=s\dfrac{137}{4272}\\\Rightarrow v_c=\dfrac{s}{\frac{4272}{137}}\\\Rightarrow v_c=\dfrac{s}{31.182}[/tex]
So, the time taken is 31.182 seconds