Answer :
[tex]V- average\ speed\ of\ Exante\ Express\ train\\t-travel\ time\ of\ Exante\ Express\ train \\ \\V= \frac{S}{t} \ \ \ \ and\ \ \ V-50= \frac{S}{t+60\%t} = \frac{S}{1.6t}\ \ \ \ and\ \ \ S=1800\\ \\V= \frac{1800}{t} \ \ \ and\ \ \ V-50=\frac{1800}{1.6t}\ \ \ \Rightarrow\ \ \ \frac{1800}{t}-50= \frac{1125}{t} \ /\cdot t\\ \\1800-50 t=1125\ \ \ \Rightarrow\ \ \ 50t=1800-1125\ \ \ \Rightarrow\ \ \ 50t=675\ /:50\\ \\t=13.5\ [h]=13\ [h]\ 30\ [min]\\\\1.6t=21.6\ [h]=21\ [h]+ 0.6\cdot60\ [min]=21\ [h]\ 36\ [min]
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[tex]V= \frac{1800}{t} =\frac{1800}{13,5} =133 \frac{1}{3} \ [km/h]\approx133.3\ [km/h]\\\\V-50\approx83.3\ [km/h][/tex]
[tex]Ans.\\ average\ speed\ of\ Exante\ Express\ train\ is\ 133.3\ km/h,\\travel\ time\ of\ Exante\ Express\ train\ is\ 13\ h\ 30\ min;\\average\ speed\ of\ Paral \ passenger \ train\ is\ 83.3\ km/h,\\travel\ time\ of\ Paral \ passenger\ train\ is\ 21\ h\ 36\ min[/tex]
[tex]V= \frac{1800}{t} =\frac{1800}{13,5} =133 \frac{1}{3} \ [km/h]\approx133.3\ [km/h]\\\\V-50\approx83.3\ [km/h][/tex]
[tex]Ans.\\ average\ speed\ of\ Exante\ Express\ train\ is\ 133.3\ km/h,\\travel\ time\ of\ Exante\ Express\ train\ is\ 13\ h\ 30\ min;\\average\ speed\ of\ Paral \ passenger \ train\ is\ 83.3\ km/h,\\travel\ time\ of\ Paral \ passenger\ train\ is\ 21\ h\ 36\ min[/tex]
