Latest Book Aptitude Question SOLUTION: How many numbers are there in all from 6000 to 6999 (both 6000 and 6999 included) having at least one of their digits repeated ?? (a) 216 (b) 356 (c) 496 (d) 504

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(#M40038164) BOOK Numerical Ability question Permutations and combinations Keep an EYE

How many numbers are there in all from 6000 to 6999 (both 6000 and 6999 included) having at least one of their digits repeated ??

(a) 216
(b) 356
(c) 496
(d) 504

Asked In Book Nikhil Arora (9 years ago)

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ASHISH KUMAR  (9 years ago)

total nos. between 6000 and 6999=1000
nos. when no digits are repeated=9*8*7=504
consider a four digit no. between 6000 and 6999
at one's place=9 digits can be used (6 cannot be used as it used at 1000th place)
at 10's place=8 digits can be used
at 100's place 7 digits can be used
at 1000's place only one digit can be used(i.e.6)
reqd. nos.=1000-504=496
c is correct option

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krishna kanth  (9 years ago)

ans: c

total no's are 1000
now i will remove numbers which are not repeated from total
so ,it is first digitis always 6 it is fixed
and remaining 3 can be arranged from 9 digits in 9p3 ways
so answer is 1000-9p3=1000-504=496

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