1st question is simultaneous equations, 1st find the speed of the journey there where speed =distance/time
then the speed of the journey back.
Then do 2 equations as shown where helicopter speed is h and wind is w
you have 2 equations
h + w = speed of journey there
h - w = speed of journey back
adding the 2 equations would give 2h=speed of journey there = speed of journey back
then do the same but subtract the 2nd equation from the 1st