Question

We drive a distance of $1km$ at $16kmph$. Then we drive an additional distance of $1km$ at $32kmph$. What is our average speed?

• A. $21.3kmph$
  
• B. $22kmph$
  
• C. $23kmph$
  
• D. $24kmph$
  

Answer 1

The correct option is A $21.3kmph$

Time taken in first 1 km, $t_1=\frac{distance}{velocity}=\frac{1}{16}=0.0625hr$
Time taken in second 1 km, $t_2=\frac{distance}{velocity}=\frac{1}{32}=0.03125hr$
Total time taken $t=0.0625+0.03125=0.09375h$
Total distance covered $S=1+1=2km$
Average velocity $v=\frac{D}{t}=\frac{2}{0.09375}=21.3km/hr$