In terms of Emily's equal steps, the length of the ship is 84.
Apply relative velocity formula for the forward and backward steps as follows;
Forward motion;
[tex](V - V_s )t = d\\\\(\frac{200}{t} - \frac{d}{t} ) t = d[/tex]
backward motion;
[tex](V + V_s) t = d\\\\(\frac{42}{t} + \frac{d}{t} ) t= d[/tex]
Solve the forward and backward motion together;
[tex](\frac{200}{t} - \frac{d}{t} )t = (\frac{42}{t} + \frac{d}{t} )t \\\\\frac{200}{t} - \frac{d}{t} = \frac{42}{t} + \frac{d}{t}\\\\\frac{200-42}{t} = \frac{d+ d}{t} \\\\2d = 168\\\\d = \frac{168}{2} \\\\d = 84[/tex]
Thus, in terms of Emily's equal steps, the length of the ship is 84.
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