Question 761829
Let x be the speed of plane in still air and y be the wind speed.

Step 1: Flying into the wind, effective speed = {{{(x - y)}}}. Distance of 1980 is covered in 5.5 hours. Distance = Speed * time.
So
{{{(x - y) * 5.5 = 1980}}} or {{{x - y = 1980/5.5 = 360}}}  ---> eqn 1

Step 2: Flying with the wind - effective speed = {{{(x + y)}}}
Applying the same formula distance = speed * time

{{{(x + y) * 4.5 = 1980}}} or {{{x + y = 1980/4.5 = 440}}} --- eqn 2

Step 3:
From eqn 1, x = y + 360. Substituting for x in eqn 2

{{{y + 360 + y = 440}}} 
{{{2*y = 80}}} or {{{y = 40}}}

Step 4:
Since y = 40, {{{x = y + 360 = 400}}}

Speed of plane in still air = {{{highlight(400)}}} and wind speed = {{{highlight(40)}}}

:)