Question 62430: a biker rode 3 hours with a wind of 6 km/h. when he was returnin against the same wind it took 5 hours. what his speed in still air. Answer by funmath(2933) (Show Source):
You can put this solution on YOUR website! a biker rode 3 hours with a wind of 6 km/h. when he was returning against the same wind it took 5 hours. what his speed in still air.
The formula for distance is , d=distance, r=rate (or speed) and t=time.
Let the rate in still air be: x
Let the rate with the wind be: x+6
Then the distance with the wind is: 3(x+6)
The rate against the wind is: x-6
The distnce against the wind is: 5(x-6)
The biker drove the same distance up and back, so we can set the two distances equal to each other.
3(x+6)=5(x-6)
3x+18=5x-30
-3x+3x+18=-3x+5x-30
18=2x-30
18+30=2x-30+30
48=2x
48/2=2x/2
24=x
The rate or speed in still air is x=24 km/h
Happy Calculating!!!
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