20 और 80 के बीच कितनी अभाज्य संख्याएँ हैं?

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RRB Group D 2 Sept 2022 Shift 3 Official Paper
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  1. 15
  2. 13
  3. 16
  4. 14

Answer (Detailed Solution Below)

Option 4 : 14
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RRB Group D Full Test 1
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दिया गया है:

20 और 80 के बीच अभाज्य संख्याएँ।

प्रयुक्त अवधारणा:

एक अभाज्य संख्या को केवल 1 या स्वयं से विभाजित किया जा सकता है।

गणना:

माना x एक अभाज्य संख्या है।

⇒ x = 1 × x

20 और 80 के बीच अभाज्य संख्याएँ,

23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79

अतः, 20 और 80 के बीच 14 अभाज्य संख्याएँ हैं।

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