Question 656697
<pre>

Speed = {{{Distance/(Time)}}} =

{{{(700m)/(35sec)}}}

Since 1000m = 1km,  {{{1km/(1000m)}}} = 1, we can multiply by that
without changing the value.

[We put "m" on the bottom to cancel the "m" on the top]:

{{{(700m)/(35sec)}}}×{{{1km/(1000m)}}}

Since 60sec = 1min,  {{{60sec/(1min)}}} = 1, we can multiply by that
without changing the value.

[We put "sec" on the top to cancel the "sec" on the bottom]:

{{{(700m)/(35sec)}}}×{{{1km/(1000m)}}}×{{{60sec/(1min)}}}

Since 60min = 1hr,  {{{(60min)/(1hr)}}} = 1, we can multiply by that
without changing the value.

[We put "min" on the top to cancel the "min" on the bottom]:

{{{(700m)/(35sec)}}}×{{{1km/(1000m)}}}×{{{60sec/(1min)}}}×{{{(60min)/(1hr)}}}

Now we cancel the m's:

{{{(700cross(m))/(35sec)}}}×{{{1km/(1000cross(m))}}}×{{{60sec/(1min)}}}×{{{(60min)/(1hr)}}}

Now we cancel the sec's:

{{{(700cross(m))/(35cross(sec))}}}×{{{1km/(1000cross(m))}}}×{{{60cross(sec)/(1min)}}}×{{{(60min)/(1hr)}}}

Now we cancel the min's:

{{{(700cross(m))/(35cross(sec))}}}×{{{1km/(1000cross(m))}}}×{{{60cross(sec)/(1cross(min))}}}×{{{(60cross(min))/(1hr)}}}

and all we have left is

{{{(700)/(35)}}}×{{{1km/(1000)}}}×{{{60/(1)}}}×{{{60/(1hr)}}}

{{{(700*60*60km)/(35*1000hr)}}}

{{{2520000/35000}}}{{{km/hr}}}

72{{{km/hr}}}

Edwin</pre>