Question 770922
520/x = 160/x - 90
Cross multiply
520(x - 90) = 160x
520x - 46800 = 160x
520x - 160x = 46800
360x = 46800
x = 130
Speed of plane = 130mph
Car's speed = 40mph
Proof:
520/130 = 160/40
40 = 40
Hope this helps.
:-)