Smith travels along four sides of a square at speeds of 20, 10, 40 and 30 km/hr respectively. The average speed of Smith is:

Smith travels along four sides of a square at speeds of 20, 10, 40 and

1.	Smith travels along four sides of a square at speeds of 20, 10, 40 and 30 km/hr respectively. The average speed of Smith is:
A.	32.4 km/hr
B.	18.4 km/hr
C.	25 km/hr
D.	19.2 km/hr
Answer» E.