Question

pranali and prasad starting walking to the east and to the north respectively from the same point and at the same speed. After 2 hours distance between them was15√2km. Find their speed per hour.​

Answer 1

Answer:

speed is 7.5km/hr

Step-by-step explanation:

Let their speed be 'x' km/h

We know, distance = speed × time

In two hours,

Distance travelled by both = '2x' km

Let their starting point be 'O', and Pranali and Prasad reach the point A in the East and point B in the north direction respectively.

Clearly, AOB is a right-angled triangle, So By Pythagoras theorem

(Hypotenuse)2 = (base)2 + (Perpendicular)2

(AB)2 = (OA)2 + (OB)2

As, AB = distance between them = 15√2 km

And OA = OB = distance travelled by each = 2x

⇒ (15√2)2 = (2x)2 + (2x)2

⇒ 450 = 8x2

⇒ x2 = 56.25

⇒ x = 7.5 km/h