Question 720508
Let {{{ p }}} = the speed of the plane in still air
Let {{{ w }}} = the speed of the wind
{{{ p + w }}} = the plane's speed flying with the wind
{{{ p - w }}} = the plane's speed flying into the wind
-------------------------------------------
given:
(1) {{{ p + w = 135 }}} mi/hr
92) {{{ p - w = 93 }}} mi/hr
Now add the equations
{{{ 2p = 228 }}}
{{{ p = 114 }}}
Plug this value back into (1) or (2)
(1) {{{ 114 + w = 135 }}}
(1) {{{ w = 21 }}}
The speed of the plane in still air is 114 mi/hr
The speed of the wind is 21 mi/hr