Question 258432
This is an RTD problem. WE can create a table based on the given information:
PLANE . . . . . .rate . . . . . . . .time . . . . . . . distance
against . . . . . .r-c . . . . . . . .6  . . . . . . . . . . .900
with . . . . . . .. r+c . . . . . . .. 5 . . . . . . .. . . . .900
RT=D
or r = D/T
r-c = 150
r+c = 180
adding down we get
 2r = 330
r = 165
rate with no wind is 165 mph
c = 15 mph