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Two consecutive odd whole numbers are selected. The difference between the reciprocal of the two numbers is 2/99. Determine the two numbers

User FreddieE
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1 Answer

4 votes

Answer:

x = 9 (first odd number)

x + 2 = 11 (second odd number)

Explanation:

Let

x =first odd number

x + 2=second odd number

given:

1/x - 1/(x + 2) = 2/99

Find the LCM

(x+2)-x / x(x+2)=2/99

x+2-x / x(x+2)=2/99

common denominator x( x + 2)

2 / x(x + 2) = 2/99

Take the reciprocal of both sides

1/2x(x + 2) = 99/2

multiply both by 2

x(x +2) = 99

Expand the left side

x^2 + 2x = 99

add 1 to both sides

x^2 + 2x + 1 = 100

express the left side as a square

(x + 1)^2 = 100

Square root of both sides

x + 1 = 10 or x + 1 = -10

taking the positive root only

x = 9 (first odd number)

x + 2 = 11 (second odd number)

check:

1/9 - 1/11 = 2/99

11/99 - 9/99 = 2/99

2/99 = 2/99

User BlueDragonX
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