Question 1039678
Convert the target speed to feet/sec.
{{{40}}}{{{mi/hr}}}*{{{1/3600}}}{{{hr/s}}}*{{{5280}}}{{{ft/mi}}}={{{58.7}}}{{{f/s}}}
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Convert the distance between them to feet.
{{{40}}}{{{yds}}}{{{3}}}{{{feet/yd}}}={{{120}}}{{{ft}}}
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So the object is moving relative to the target at a speed of 
{{{700-58.7=641.3}}}{{{f/s}}}
So then the time for the object to travel 120 feet is,
{{{t=120/641.3=0.19}}}{{{s}}}