Question 124932
Let wind speed = {{{w}}}
Let the speed of the plane in still air = {{{p}}}
With the wind, the combined speed is {{{p + w}}}
Against the wind, the combined speed is {{{p - w}}}
{{{d = r*t}}} is the general formula
The distance is the same, coming and going
{{{(p - w)*t[1] = (p + w)*t[2]}}}
{{{t[1] = 7.5}}} hrs
{{{t[2] = 3}}} hrs
{{{(p - w)*7.5 = (p + w)*3}}}
{{{7.5p - 7.5w = 3p + 3w}}}
{{{4.5p = 10.5w}}}
{{{p = (7/3)w}}}
Also given is the distance, 750 mi
{{{(p + w)*3 = 750}}}
{{{((7/3)w + w)*3 = 750}}}
{{{(10/3)w*3 = 750}}}
{{{10w = 750}}}
{{{w = 75}}} mi / hr answer
Check answer
{{{p = (7/3)w}}}
{{{p = (7/3)*75}}}
{{{p = 175}}}
{{{(p - w)*7.5 = (p + w)*3}}}
{{{(175 - 75)*7.5 = (175 + 75)*3}}}
{{{750 = 250*3}}}
{{{750 = 750}}}
OK