SOLUTION: Average... Determine the average of the two real numbers x/3 and 2x/5.

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Question 120259: Average...
Determine the average of the two real numbers x/3 and 2x/5.
Found 2 solutions by checkley71, Edwin McCravy:
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
[(x/3)+(2x/5)]/2 add the fractions by finding the common denominator.(15)
[(5x+3*2x)/15]/2
[(5x+6x)/15]/2
[11x/15]/2
(11x/15)*1/2
11x/(15*2)
11x/30 answer.

Answer by Edwin McCravy(20086) About Me  (Show Source):
You can put this solution on YOUR website!
SOLUTION BY EDWIN:
Average...
Determine the average of the two real numbers x/3 and 2x/5. 

Use the formula

                          FIRST NUMBER + SECOND NUMBER 
AVERAGE OF TWO NUMBERS = ------------------------------
                                       2


AVERAGE OF TWO NUMBERS = %28x%2F3+%2B+%282x%29%2F5%29%2F2

Write the 2 on the bottome as 2%2F1 so everything
will be a fraction:

AVERAGE OF TWO NUMBERS = %28x%2F3+%2B+%282x%29%2F5%29%2F%282%2F1%29

Put parentheses around all terms top and bottom:

AVERAGE OF TWO NUMBERS = %28%28x%2F3%29+%2B+%28%282x%29%2F5%29%29%2F%28%282%2F1%29%29


The LCD of all three denominators 3,5,and 1 is 15,
so multiply every term on top and bottom by 15, written
as %2815%2F1%29:
(15/1)
AVERAGE OF TWO NUMBERS = %28%2815%2F1%29%28x%2F3%29+%2B+%2815%2F1%29%28%282x%29%2F5%29%29%2F%2815%2F1%29%282%2F1%29

Cancel the 3 into the 15 in the first term on top.
Cancel the 5 into the 15, getting 3 in the second term on top.

                           5          3 
AVERAGE OF TWO NUMBERS = 

So we end up with

AVERAGE OF TWO NUMBERS = %285x+%2B+6x%29%2F30 or

AVERAGE OF TWO NUMBERS = %2811x%29%2F30

Edwin