A person goes to his office at 1/3rd of the speed at which he returns from his office. If the avg speed during the whole trip is 30m/h. what is the speed of the person while he was going to his office?
Choose the correct choice from the following answers:
A) 8km/h  B) 9km/h  C) 10km/h  D) 11km/h  E) 20km/h
u = k , v= 3k   \inline \therefore \frac{2uv}{u+v}\: \: \Rightarrow \frac{2\times k\times 3k}{(k+3k)}=30   \inline \Rightarrow 1.5k = 30   \inline \Rightarrow k=20km/h   20km/h
<result>E</result>
A person goes to his office at 1/3rd of the speed at which he returns from his office. If the avg speed during the whole trip is 30m/h. what is the speed of the person while he was going to his office?