Question

If the reciprocal of a number is multiplied by 1 less than the original number, the results exceed 1/2 the reciprocal of the original number by 5/8. Find the number.

Answer 1

4

Explanation:

Let's try this a different way than perhaps the usual way. Let r represent the reciprocal of the number.

r(1/r -1) -1/2r = 5/8

1 -r -1/2r = 5/8 . . . . . . eliminate parentheses

-3/2r = -3/8 . . . . . . . . collect terms, subtract 1

(-3/2)/(-3/8) = 1/r = 4 . . . . . divide by (-3/8)r because we actually want 1/r

The number is 4.

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Check

The reciprocal of the number is 1/4.

1 less than the original number is 4 -1 = 3. The product of these is 3/4.

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Half the reciprocal of the original number is (1/2)(1/4) = 1/8.

Then the difference between these is ...

3/4 -1/8 = (6 -1)/8 = 5/8 . . . . as required.