How many prime numbers exist between 1 and 50 inclusive?
Answer and explanation
Correct answer: D. 15
- Step 1: List all primes <= 50: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47. Step 2. Counting them gives exactly 15 prime numbers. Answer: 15. Why not the others: 14 mistakenly misses the prime 47; 16 erroneously counts 1 or composite 49; 13 omits both 41 and 43 from the total count.
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