Question

9. John runs for 10 min. at a uniform speed 9km/h. At what speed should he run for the
next 20 min. ​

Answer 1

Answer:

13.5 km/h

Explanation:

s1=v1t1

And, s2=v2t2

Average speed v=ts=t1+t2s1+s2

⟹v=t1+t2v1t1+v2t2

⟹v2=t2v(t1+t2)−v1t1

⟹v2=2012(10+20)−9×10

⟹v2=13.5km/h

Answer 2

13.5 km/hr

the boy should run at a speed of 13.5 km/hr for the next 20 minutes