# Help a rookie see the difference?

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Posted by MathBard on October 27, 2002 at 03:17:45:

In Reply to: WRONG Mr K: that should be R + r and R - r ; see Mr S's :)) posted by Denis Borris on October 27, 2002 at 02:56:53:

Mathematically they seem the same to me except that Soroban divided from 2 sec to per/sec BEFORE he sat up the problem. I worked both and got the same answer, so i assume they are each correct.
Here's my question: Is there a notation thingy that requires one to use the upper case R and the lower case r for the two unknowns, or can you make up your own like MR K. did? Is THAT what you are correcting?

the humbly Curious
MB

: : : I am struggling with Algebra and my brain just can't handle word problems. Help is appreciated.

: : : With the wind, a quarterback passes a football 140 feet in 2 seconds. Against the wind, the same pass would have traveled 80 feet in 2 seconds. Find the rate of the pass and the rate of the wind.

: : : I'm thinking... (since d=r.t)

: : : 140=R.2
: : : 80=R.2

: : : If so, why can't I come up with a logical answer?
: : *******************************************
: : 1) What do you want to find (unknowns)? 2 unknowns:

: : the rate of the pass = P......and
: : the rate of the wind = W

: : 2) What are given: distance and time (Your choice of equation is correct)

: : 3) With the wind: Rate= P + W

: : 140 = (P +W)*2

: : 4) Against the wind: Rate = P - W

: : 80 = (P-W)*2

: : 5) In (3) and (4) you have two equations and two unknowns - solve it....

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