Question

Problem: A horse rider went a mile in 5 minutes with the wind and returned in 7 minutes against the wind. How fast could he ride a mile if there was no wind?

Answer 1

He could ride 6 minutes with no wind.


let speed with wind be a=5
speed against wind be b=7
speed=1/2(a+b)
i.e 1/2(7+5)
=6minute

THANKS!

Answer 2

Answer: $\frac{6}{35}\ mile/min$

Step-by-step explanation:

• Let the speed of rider and wind be x and y respectively.
• Given distance is 1 mile.
• Now according to question,

        $\frac{1}{x+y}=5$  when he moves with the wind.

   ⇒ $x + y=\frac{1}{5}$       eq.1

   And, $\frac{1}{x-y}=7$ when he moves opposite to the wind.

    ⇒ $x-y=\frac{1}{7}$       eq.2

Adding the eq.1 and eq.2 we get,

      x + y + x - y= $\frac{1}{5}+\frac{1}{7}$

  ⇒ 2x=$\frac{12}{35}$

  ⇒ x = $\frac{6}{35}\ mile/min$

• Hence, the required speed at which the rider will ride if there was no wind  is  $\frac{6}{35}\ mile/min$.

        #SPJ3