Question 935168
A ship leaves port at 12:00 pm (noon) and sails east at 10 miles per hour.  Another leaves the same port at 1:00 pm and sails north at 20 miles per hour.  At what time are the ships 50 miles apart?
====================
t = 0 at 1 PM
Distance from port:
Eastbound = 10t + 10
Northbound = 20t
---
{{{d^2 = (10t+10)^2 + (20t)^2}}}
{{{(10t+10)^2 + (20t)^2 = 50^2 = 2500}}}
{{{100t^2 + 200t + 100 + 400t^2 = 2500}}}
{{{500t^2 + 200t + 100 = 2500}}}
{{{5t^2 + 2t - 24 = 0}}}
(5t + 12)*(t - 2) = 0
t = 2 hours (Ignore the negative solution)
--> 3 PM