Question 599626
Let {{{ w }}} = the wind speed in mi/hr
Let {{{ s }}} = the speed in mi/hr of the plane in still air
Let {{{ t }}} = time of flights  in hrs both with and against the wind
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Flying with the wind:
{{{ 4131 = ( s + w )*t }}}
(1) {{{ 4131 = ( 425 + w )*t }}}
Flying against the wind:
{{{ 3519 = ( s - w )*t }}}
(2) {{{ 3519 = ( 425 - w )*t }}}
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(1) {{{ t = 4131 / ( 425 + w ) }}}
(2) {{{ t = 3519 / ( 425 - w ) }}}
{{{ 4131 / (425 + w ) = 3519 / ( 425 - w ) }}}
Multiply both sides by {{{ ( 425 + w  )*( 425 - w ) }}}
{{{ 4131*( 425 - w ) = 3519*( 425 + w ) }}}
{{{ 1755675 - 4131w = 1495575 + 3519w }}}
{{{ 7650w = 1755675 - 1495575 }}}
{{{ 7650w = 260100 }}}
{{{ w = 34 }}}
The wind speed is 34 mi/hr
check:
(1) {{{ 4131 = ( 425 + 34 )*t }}}
(1) {{{ 4131 = 459t }}}
{1) {{{ t = 9 }}} hrs
and
(2) {{{ 3519 = ( 425 - 34 )*t }}}
(2) {{{ 3519 = 391t }}}
(2) {{{ t = 9 }}} hrs
OK