Question 328411
You need 2 equations, one going with the wind
and one going against the wind
Let {{{w}}} = wind speed
Let {{{a}}} = speed of plane in still air
given:
with the wind:
{{{t[1] = 2.5}}} hrs
{{{d = 625}}} mi
against the wind:
{{{t[2] = 4.1667}}}
{{{d = 625}}} mi
--------------
{{{625 = (a+w)*2.5}}}
{{{625 = (a-w)*4.1667}}}
This is 2 equations with 2 unknowns, so it's solvable
(1) {{{625 = 2.5a + 2.5w}}}
(2) {{{625 = 4.1667a - 4.1667w}}}
Multiply both sides of (1) by {{{4.1667/2.5}}}
and add (1) and (2)
I can't find my calculator, so you can do it