Official Guide Explanation:
Problem Solving #89




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Solution and Metadata

Question: 89
Page: 164
Difficulty: 6 (Moderately Difficult)
Category 1: Arithmetic > Fractions >
Category 2: Arithmetic > Properties of Integers > Factors and Multiples

Explanation: To keep things simple, call the product of the integers from 100 to 200, inclusive, p. Thus, s = p. Since t is the same, only it also multiplies the total by 201, t = 201p.

To find (1/(s)) + (1/(t)), start in terms of p:

(1/(p)) + (1/(201p))

= (201/(201p)) + (1/(201p))

= (202/(201p))

We're looking for the same answer, but in terms of t. Since t = 201p, we can directly substitute t for the denominator:

= (202/(t)), choice (D).

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