There is a river with a current of 10 mph. On the river there are two boats.
One boat is going upstream at 10 mph real speed. one boat is going
downstream at 10 mph real speed. As the boats pass each other what is
the formula to calculate the relative speeds?

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Clarification of Question by anewwaytopush-ga on 13 Oct 2005 12:29 PDT

to clairfy the question. What is the formula to calculate water
velocity on each boat. refer to www.newlifter.com   down load the
analysis into Excel and find the formula he used.   Is he right?  
a+b/2  and a-b/2  odd thing is a-b always yeilds 0 when the speeds are
the same and 0/2 makes no sense.

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Can't remember if it is correct or not but:

Take the direction down stream to be positive

then

aVb = Va - Vb

aVb is velocity of boat A relative to boat B 
Va is the velocity of boat A
Vb is the velocity of boat B

Using your example:
aVb = Va - Vb
aVb = 10 - -10
aVb = 20 mph (because they are going towards each other and are
parallel to each other)

To politicalguru-ga 
The question is about the machine at www.newlifter.com

So both boats travel at 10 mi/hr. One boat goes agaist the current,
the other goes with the current. The current is 10 mi/hr also.

One hour after the two boats passed each other, 

>>>the boat going upstream travelled 10 miles.
>>>the boat going downstream travelled 10 miles.
>>>the point on the current where the two boats met travelled 10 miles.

>>>the distance between the upstream boat and the point on the current
is 10+10 = 20 miles.
>>>the distance between the upstream boat and the point on he current
is zero. Zero can be 10 minus 10, which is the difference of the
distances travelled by the downstream boat and the point on the
current.

distance = velocity * time 
Or, velocity = distance / time.
>>>>For the upstream boat, velocity of point on the current = 20mi / 1hr = 20 mph.
>>>>For the downstream boat, velocity of point on the current =  0mi / 1hr = 0 mph.

Can you get the formulas now?