Question

400 तक 3 या 7 से विभाजित होने वाली कुल संख्या कितनी है?
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Answer 1

Answer:

19

Step-by-step explanation:

the first no. which are divisible by both 3 and 7

are 21 so, a=21 d =21 last term =399

by AP      L=a+(n-1)d

21+(n-1)21=399

n-1=399-21/21

n-1=378/21=18

n=19