"Published in Newark, California, USA"
Felix rode 18 miles downstream and back to the same place where he started, in 3 hours and 12 minutes. Find the rate of Felix in still water if the velocity of the stream is 3 miles per hour.
Solution:
To illustrate the problem, it is better to draw the figure as follows
 |
| Photo by Math Principles in Everyday Life |
Let s = be the distance traveled by Felix in upstream / downstream
v = be the velocity or speed of Felix in still water
v1 = be the velocity in downstream
v2 = be the velocity in upstream
t1 = time traveled in downstream
t2 = time traveled in upstream
If the word statement says "Felix rode 18 miles downstream and back to the same place where he started, in 3 hours and 12 minutes.", then the working equation is
Substitute the values of t1 and t2 so that we can solve for the value of v which is Felix' speed or velocity in still water.
By using quadratic formula, the value of v is
We need to choose the positive sign not the negative sign because the value of velocity will be negative which is not accepted as a final answer. Therefore, the velocity or speed of Felix in still water is
