we can use an average between the first 3 and the second 2 and the average must be 50 so
[tex]\frac{53+x}{2}=50[/tex]where x is the time of the seconds 2 runners
now we solve x
[tex]\begin{gathered} 53+x=50\times2 \\ x=100-53 \\ x=47 \end{gathered}[/tex]the time of the second runners must be 47 seconds per lap
