<PRE><B>Question 719546</B>
train has traveled 60 when the car is crossing the track

After x hours car will be at a distance of 45x miles

The train will be at a distance of 60x+60 .

they are at right angles with respect to the intersection

(60x+60)^2+(45x)^2=100^2


3600x^2+7200x+3600+2025x^2=10000

5625x^2+7200x-6400=0

factorize.
we get two values x=0.6 OR -1.88

ignore negative value.

so 0.6 hours</PRE>