SOLUTION: The sum of a number and it's inverse is 3 29/52 Find the number

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Question 1190353: The sum of a number and it's inverse is 3 29/52
Find the number

Answer by greenestamps(13215) About Me  (Show Source):
You can put this solution on YOUR website!


The sum of a number and cross%28%22it%27s%22%29 its cross%28inverse%29 reciprocal is 3 29/52.

Using formal algebra....

let the number be x; then the reciprocal is 1/x

3 29/52 = (156+29)/52 = 185/52

x%2B1%2Fx=185%2F52
52x%2B52%2Fx=185
52x-185%2B52%2Fx=0
52x%5E2-185x%2B52=0

Try factoring that; or use the quadratic formula....

It does in fact factor:

%2813x-4%29%284x-13%29=0

x=4%2F13 or x=13%2F4

ANSWER: The number and its reciprocal are, in either order, 4/13 and 13/4

The answer can be obtained far more easily using logical reasoning, simple trial and error, and easy arithmetic.

(1) Since the sum is a bit more than 3, the larger number must be a bit more than 3.
(2) Since the denominator of the sum is 52, the most likely denominators of the two fractions x and 1/x are 13 and 4.

So try 13/4 and 4/13 for the two numbers and verify that their sum is indeed 3 29/52.