\(v_1=5\)m/s
\(v_2=45\)km/h=12,5m/s
\(v_3=7,5\)m/s
\(\Rightarrow v_2>v_3>v_1\)\(\Rightarrow\)Hồng,Khánh,Đức
\(45\left(\dfrac{km}{h}\right)=12,5\left(\dfrac{m}{s}\right)\)
\(\Rightarrow12,5\left(\dfrac{m}{s}\right)>7,5\left(\dfrac{m}{s}\right)>5\left(\dfrac{m}{s}\right)\)
\(\Rightarrow45\left(\dfrac{km}{h}\right)>7,5\left(\dfrac{m}{s}\right)>5\left(\dfrac{m}{s}\right)\)