Question 97430
1000/(500-x)=2.5 cross multiply
2.5(500-x)=1000
1250-2.5x=1000
-2.5x=1000-1250
-2.5x=-250
x=250/-2.5
x=100 kph. is the speed of the wind.
proof
1000/(500-100)=2.5
1000/400=2.5
2.5=2.5