Amar and Ashok are two friends standing at a corner of a rectangular garden. They wanted to drink water. Amar goes due north at a speed of 50 m/min and Ashok due west at a speed of 60 m/min. They travel for 5 minutes. Amar reaches the tap and drinks water. How far(minimum distance) is Ashok from the tap now?

Answer : 

Complete question is " Amar and Ashok are two friends standing at a corner of a rectangular garden. They wanted to drink water. Amar goes due north at a speed of 50 m/min. and Ashok due west at a speed of 60 m/min. They travel for 5 minutes. Amar reaches the tap and drink water. But somebody told Ashok to go towards point C. As there was to other tap. Find the min. distance Ashok has to travel to reach point C.

As speed of amar  =  50 m /min 
Distance  =  Speed $\times$ Time 
So after 5 min total distance covered by Amar  = 50 $\times$ 5  =  250 m 
So, AC   =  250 m 

And
As speed of Ashok  =  60 m /min 
Distance  =  Speed $\times$ Time 
So after 5 min total distance covered by Ashok  = 60 $\times$ 5  =  300 m 
So, AF   =  300 m 

Now Ashok goes toward C as that is the Tap . So Ashok is far from the tap ( minimum ) = length of FC 

Now we apply Pythagoras theorem in triangle FAC 

FC²  = AF^​2  + AC² 

FC² = 300²  + 250² 

FC² = 90000  + 62500

FC² = ​152500 

FC  = $\sqrt{152500} = \sqrt{50 \times 50 \times 61} = 50\sqrt{61}$
So,
Ashok is $50\sqrt{61}$ m far from the tap .                                ( Ans )