Question 760711
Think of one motorcyclist as standing still and
the other one traveling at the sum of their speeds
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Let {{{ s }}} = the speed of the slower one
{{{ s + 4 }}} = the speed of the faster one
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{{{ 392 = ( s + s + 4 )*3 }}}
{{{ 392 = ( 2s + 4 )*3 }}}
{{{ 392 = 6s + 12 }}}
{{{ 6s = 380 }}}
{{{ s = 63.333 }}}
{{{ s + 4 = 67.333 }}}
The speed of the slower one is 63.333 mi/hr
The speed of the faster one is 67.333 mi/hr
check:
slower one:
{{{ d[1] = 63.333*3 }}}
{{{ d[1] = 190 }}} mi
faster one:
{{{ d[2] = 67.333*3 }}}
{{{ d[2] = 202 }}} mi
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{{{ d[1] + d[2] = 190 + 202 }}}
{{{ d[1] + d[2] = 392 }}}
OK