Question 1155140
r, speed of plane with no wind
w, wind speed
G, the time going
2G, the time back
D, one-way distance
-
G=7
D=644


{{{system(r+w=D/G,r-w=D/(2G))}}}

.
.
{{{highlight(r=(3D)/(4G))}}}


{{{r=(3*644)/(4*7)}}}

{{{highlight(highlight(r=69))}}}-------speed for plane when no wind


{{{highlight(highlight(w=23))}}}-------speed of wind