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Let n be a natural number such that $$\frac{1}{2}$$ + $$\frac{1}{3}$$ + $$\frac{1}{7}$$ + $$\frac{1}{n}$$ is also a natural number. Which of the following statements is not true ?
Answer & Solution
Correct Answer:
Option
D
$$\eqalign{
& = \left( {\frac{1}{2} + \frac{1}{3} + \frac{1}{7}} \right) + \frac{1}{n} \cr
& = \frac{{\left( {21 + 14 + 6} \right)}}{{42}} + \frac{1}{n} \cr
& = \left( {\frac{1}{{42}} + \frac{1}{n}} \right) \cr} $$
This sum is a natural number when n = 42
So, each one of the statements that 2 divides ; 3 divides n and 7 divides n is true.
Hence, n > 84 is false
This sum is a natural number when n = 42
So, each one of the statements that 2 divides ; 3 divides n and 7 divides n is true.
Hence, n > 84 is false
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