When a positive integer n has 4 different factors, n=?
1) n has only 1 prime factor
2) n<10
==> In the original condition, there is 1 variable(n), which should match with the number of equations. Then, 1 euqation is needed as well. For 1) 1 equation, for 2) 1 equation, which is likely to make D the answer.
For 1),\(n=2^3, 3^3\) ,…, which is not sufficient.
For 2), onlyn=\(2^3\) is possible, which is unique and sufficient.
Hence, the answer is B.
Answer: B
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1) n has only 1 prime factor
2) n<10
==> In the original condition, there is 1 variable(n), which should match with the number of equations. Then, 1 euqation is needed as well. For 1) 1 equation, for 2) 1 equation, which is likely to make D the answer.
For 1),\(n=2^3, 3^3\) ,…, which is not sufficient.
For 2), onlyn=\(2^3\) is possible, which is unique and sufficient.
Hence, the answer is B.
Answer: B
...
