[tex]\bf 75\, km = 75 \cdot 1000\, m = 75000\,m[/tex]
[tex]\bf 50\, min = 50 \cdot 60\, s = 3000\,s[/tex]
[tex]\bf v=\dfrac{\Delta d}{\Delta t} =\dfrac{75000m}{3000s} = \boxed{\boxed{\bf 25\dfrac{m}{s}}}[/tex]
[tex]\bf v=25\dfrac{m}{s} =25:\dfrac{km}{h} =25:\dfrac{1000m}{3600s}[/tex]
[tex]\bf v=25 \cdot \dfrac{3600}{1000} =\dfrac{25 \cdot 36}{10} =\dfrac{900}{10}\dfrac{km}{h}[/tex]
[tex]\bf \implies \boxed{\boxed{\bf v=90\dfrac{km}{h} }}[/tex]
Bafta! :)
#copaceibrainly
