Question

rakesh runs at 5/4 of his usual speed and reaches the playground 5 min earlier . What is his usual time.. plzz help me and post the correct answer..

Answer 1

Here is the clear explanation ! Hope you understand !

Answer 2

Answer:  The usual time of Rakesh is 25 minutes.

Step-by-step explanation: Given that Rakesh runs at five-fourth of his usual speed and reaches the playground 5 minutes earlier.

We are to find the usual time of Rakesh.

Let s and t represents the original speed and the original time taken by Rakesh.

Then, we have

$\dfrac{distance}{t}=s\\\\\Rightarrow distance=s\times t~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)$

When the speed is five-fourth of the original speed t, then the time will be (t - 5).

So, we have

$distance=\dfrac{5}{4}s(t-5)\\\\\\\Rightarrow st=\dfrac{5s}{4}(t-5)~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~[\textup{from equation (i)}]\\\\\\\Rightarrow t=\dfrac{5}{4}(t-5)\\\\\\\Rightarrow 4t=5t-25\\\\\Rightarrow 5t-4t=25\\\\\Rightarrow t=25.$

Thus, the usual time of Rakesh is 25 minutes.