Q.Number of Prime Numbers between 1 and 20 ? | ā§§ ā§° āĻĒā§°āĻž ā§¨ā§Ļ āĻ˛ā§ āĻāĻŋāĻŽāĻžāĻ¨āĻāĻž āĻŽā§āĻ˛āĻŋāĻ āĻ¸āĻāĻā§āĻ¯āĻž (Prime Numbers) āĻāĻā§ ?
A) 6 B) 7 C) 8 D) 9
Solution | āĻ¸āĻŽāĻžāĻ§āĻžāĻ¨
Prime numbers from 1 to 20 are (ā§§ ā§° āĻĒā§°āĻž ā§¨ā§ĻāĻ˛ā§ āĻŽā§āĻ˛āĻŋāĻ āĻ¸āĻāĻā§āĻ¯āĻžāĻŦā§ā§° āĻšā§āĻā§ ) 2, 3, 5, 7, 11, 13, 17, 19.
Total = 8 | āĻŽā§āĻ = ā§ŽāĻāĻž
Exam Trick : āĻĒā§°ā§āĻā§āĻˇāĻžā§° āĻā§ā§°āĻŋāĻ
Remember (āĻŽāĻ¨āĻ¤ ā§°āĻžāĻāĻ): 2, 3, 5, 7 | 11, 13, 17, 19
1–10 = 4 Prime Numbers | ā§§–ā§§ā§Ļ = ā§ĒāĻāĻž āĻŽā§āĻ˛āĻŋāĻ āĻ¸āĻāĻā§āĻ¯āĻž
11–20 = 4 Prime Numbers | ā§§ā§§–ā§¨ā§Ļ = ā§ĒāĻāĻž āĻŽā§āĻ˛āĻŋāĻ āĻ¸āĻāĻā§āĻ¯āĻž
4 + 4 = 8 | ā§Ē + ā§Ē = ā§Ž
Ans | āĻāĻ¤ā§āĻ¤ā§°: C) 8
Prime Numbers | āĻāĻŖāĻŋāĻ¤ā§° āĻā§āĻāĻž – āĻŽā§āĻ˛āĻŋāĻ āĻ¸āĻāĻā§āĻ¯āĻž : Click Here