72km/h=.....m/s     10 km/h=......km/s    240s=...... min    45 min....h

  [latex]72frac{km}{h} = 20frac{m}{s}\ 10 frac{km}{h} = 0,003frac{km}{s}\ 240s = 4 min\ 45 min = frac{3}{4}h[/latex]