A plane can fly 300 miles downwind in the same amount of time as it can travel 210 miles upwind. Find velocity of wind if plane can fly 225 mph in still air

Question

I need help figuring out this problem. Im arriving at 39.70=v which feels wrong.

Answer 1

Hi Zach,

 

Start with the Distance formula: Distance = Rate X Time   D= RT    Solve it for Time: T =D

                                                                                                                                       R

 

Since the time flying downwind (still air rate + wind rate or v) is equal to the time upwind (still air rate -wind rate or v),

make the Times equal to each other and solve the proportion by cross products.

 

T downwind = 300               T upwind = 210                  300      =    210   

                    225 + v                            225 - v             225 + v      225 - v

 

         210(225 + v) = 300(225 - v)           47250 + 210v = 67500 - 300v        

 

Subtract 47250 from both sides and add 300v to both sides.     20250 = 510v   Divide both sides by 510  v = 39.7mph

 

Zach, you were correct!!