Bài 1:
\(4p=240s\)
\(\left\{{}\begin{matrix}s''=v'':t''=2,5:120=\dfrac{1}{48}m\\v'=s':t'=240:240=1\\v=\dfrac{s'+s''}{t'+t''}=\dfrac{\dfrac{1}{48}+240}{240+120}\simeq0,6\end{matrix}\right.\)m/s
Bài 2:
\(27000m=27km\)
\(\left\{{}\begin{matrix}s'=v':t'=30:5=6km\\v=\dfrac{s'+s''}{t'+t''}=\dfrac{6+27}{5+0,5}=6\end{matrix}\right.\)km/h
Bài 3:
\(t'=s':v'=8:\left(4.3,6\right)=\dfrac{5}{9}h\)
\(v=\dfrac{s'+s''}{t'+t''}=\dfrac{8+10}{\dfrac{5}{9}+1}=\dfrac{81}{7}\)km/h
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