13. Kishore can run at 6 km/h while his son can run at3.6 km/h. They d

1.	13. Kishore can run at 6 km/h while his son can run at3.6 km/h. They decide to race and touch a goal-poston the other side of a field. Starting off together, theson touches the goal-post 12 seconds after his father.How far was the goal-post from their starting point?(Hint: Convert their speed to m/s)
Answer» Speed of Kishore = 6 km/hr= 65/18 = 5/3 m/sSpeed of son = 3.6 km/hr= 3.65/18 = 1 m/s We know,Distance = speedtime Let goal post is at distance dLet time taken by Kishore = t Then, For Kishore d = 5/3 t...... (1) For sond = 1(t + 12).....(2) Now, 5t/3 = t + 125t = 3t + 362t = 36t = 36/2 = 18 Therefore, Distance of goal post from starting point = 5/3 18= 56 = 30 m Speed of kishore=6km/hr=65/18=5/3 m/sspeed of son =3.6km/hr =3.6*5/18=1m/s

13. Kishore can run at 6 km/h while his son can run at3.6 km/h. They decide to race and touch a goal-poston the other side of a field. Starting off together, theson touches the goal-post 12 seconds after his father.How far was the goal-post from their starting point?(Hint: Convert their speed to m/s)

Answer»

Speed of Kishore = 6 km/hr= 6*5/18 = 5/3 m/sSpeed of son = 3.6 km/hr= 3.6*5/18 = 1 m/s

We know,Distance = speed*time

Let goal post is at distance dLet time taken by Kishore = t

Then, For Kishore d = 5/3 * t...... (1)

For sond = 1*(t + 12).....(2)

Now, 5t/3 = t + 125t = 3t + 362t = 36t = 36/2 = 18

Therefore, Distance of goal post from starting point = 5/3 * 18= 5*6 = 30 m

Speed of kishore=6km/hr=6*5/18=5/3 m/sspeed of son =3.6km/hr =3.6*5/18=1m/s