Question 49304
Think of this as a triangle:
distance from the car to crossing (leg) = 30
distance from the car to the train (hypotenuse) = 50
distance from the train to the crossing (leg) = b
{{{a^2 + b^2 = c^2}}}
{{{30^2 + b^2 = 50^2}}}
{{{b^2 = 1600}}}
{{{b = 40}}} The train is 40 meters from the crossing.