Question 708178
The second train's speed is 400km/5hours = 80 km/h
{{{x}}}= speed of first train in km/h
{{{x/80=7/8}}} --> {{{x=80(7/8)}}} --> {{{x=80*7/8}}} --> {{{highlight(x=70)}}}
The speed of the first train is 70 kilometers per hour.