Question 1128097
Add their speeds
Let {{{ s }}} = Mike's speed in mi/hr
{{{ 260 = ( s + 3s )*6.5 }}}
{{{ 260 = 4s*6.5 }}}
{{{ 26s = 260 }}}
{{{ s = 10 }}}
and
{{{ 3s = 30 }}}
10 mi/hr and 30 mi/hr
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check with separate rates:
Mike's equation:
(1) {{{ d = s*6.5 }}}
Doug's equation:
(2) {{{ 260 - d = 3s*6.5 }}}
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Plug (1) into (2)
(2) {{{ 260 - 6.5s = 19.5s }}}
(2) {{{ 26s = 260 }}}
(2) {{{ s = 10 }}}
OK