Question 967916
Let {{{ t }}} = time in hrs that both spend biking
Let {{{ s }}} = Samantha's speed in km/hr
------------------------------------
Fred's equation:
(1) {{{ 52 = ( s - 6 )*t }}}
Samantha's equation:
(2) {{{ 76 = s*t }}}
--------------------
(1) {{{ 52 = s*t - 6t }}}
and
(2) {{{ s = 76/t }}}
--------------------
Substitute (2) into (1)
(1) {{{ 52 = 76 - 6t }}}
(1) {{{ 6t = 24 }}}
(1) {{{ t = 4 }}}
and
(2) {{{ s = 76/4 }}}
(2) {{{ s = 19 }}}
and
{{{ s - 6 = 13 }}}
----------------
Fred bikes 13 km/hr
-------------------
check:
(1) {{{ 52 = ( s - 6 )*t }}}
(1) {{{ 52 = 13*t }}}
(1) {{{ t = 4 }}}
OK