me assume wind=23 mile shood meen wind SPEED =23 MPH
with wind...(plane speed+23)*time=490 miles
ginst wind...(plane speed-23)*time=350 miles
me assume 2 times same
2*(plane speed)*time=490+350=840, so (plane speed)*time=420
subtrakt line 2 from line 1...(23+23)*time=490-350=140
140/46=3.043478261 ours for round trip
(plane speed-23) *3.043478261 ours=350 miles
(plane speed -23)=350/3.043478261=115.0000001
plane speed=115+23=138 MPH