Question 731585
You can think of this as one cyclist standing still and
the other one approaching at the sum of their speeds
Let {{{ s }}} = the speed of the slower cyclist in mi/hr
{{{ s + 5 }}} = the speed of the faster cyclist in mi/hr
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{{{ 65 = ( s + s + 5 )*2 }}}
{{{ 65 = ( 2s + 5 )*2 }}}
{{{ 65 = 4s + 10 }}}
{{{ 4s = 55 }}}
{{{ s = 13.75 }}} 
{{{ s + 5 = 18.75 }}}
The faster cyclist's speed is 18.75 mi/hr
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check:
Faster cyclist:
{{{ d[1] = 18.75*2 }}}
{{{ d[1] = 37.5 }}}
Slower cyclist:
{{{ d[2] = s*2 }}}
{{{ d[2] = 13.75*2 }}}
{{{ d[2] = 27.5 }}}
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{{{ d[1] + d[2] = 37.5 + 27.5 }}}
{{{ d[1] + d[2] = 65 }}}
OK