An airplane flew for 6 hours with a 22-km/h tail wind. The return flight against the same wind took 8 hours. Find the speed of the plane in still air



Answer :

6 × 22 = 8 × ( s - w ) ; and s + w = 22 ; where s = the speed of the plane in still air and w = the speed of the wind ;
132 = 8 × ( s - w );
s - w = 16,5 km/h;
s+ w =  22   km/h 

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2s      = 38,5 km/h;
s = 38,5÷2;
s = 19,25 km/h ;