Question 423288
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The distances are the same, and the ratio of the times in the two directions is 3:4; that means the ratio of the speeds in the two directions is 4:3.<br>
If the plane's speed in still air is x, then the speed with the wind is x+18 and the speed against the wind is x-18:<br>
{{{(x+18)/(x-18)=4/3}}}
{{{4(x-18)=3(x+18)}}}
{{{4x-72=3x+54}}}
{{{x=126}}}<br>
ANSWER: 126 km/h<br>