Latest TCS Aptitude Question SOLUTION: How many 4-digit numbers contain no.2?

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(#M40024272) TCS Logical Reasoning question Keep an EYE

How many 4-digit numbers contain no.2?

Asked In TCS Lakshmi (10 years ago)

Unsolved Read Solution (10)

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Krishna Chaitanya Boyanapalli  (10 years ago)

i thought it be easier to understand and to solve the problem by this way
total number of four digit numbers =9000 (i.e 1000 to 9999 )
we calc the number not having no 2 in it....
now consider the
units place it can be selected in 9 ways (i.e 0,1,3,4,5,6,7,8,9)
tens place it can be selected in 9 ways (i.e 0,1,3,4,5,6,7,8,9)
hundreds place it can be selected in 9 ways (i.e 0,1,3,4,5,6,7,8,9)
thousands place can be selected in 8 ways (i.e 1,3,4,5,6,7,8,9) here '0' can not be taken
total number of numbers not having digit 2 in it =9*9*9*8 =5832
total number of numbers having digit 2 in it = 9000-5832
=3168

Is this solution Helpfull? Yes (87) | No (4)  

pritam kundu  (10 years ago)

10*10*10*9-9*9*9*8=3168

Is this solution Helpfull? Yes (8) | No (1)  

mehak jindal  (10 years ago)

total of 4 digit no=9000
total of 4 digits donot contain 2=5832
ans 9000-5832=3168

Is this solution Helpfull? Yes (7) | No (5)  

lucky  (10 years ago)

desired result=total no of 4 digit no - total no of 4 digit no not containing 2
result=9*10*10*10-8*9*9*9=3168

Is this solution Helpfull? Yes (6) | No (2)  

sangram badi  (10 years ago)

no of 2 betwn
2000 to 2999= 1000(for 1000 place)
for 100 place = 900
for 10 place = 900
for 1 place = 900
so 1000+900+900+900 = 3700 2's present

Is this solution Helpfull? Yes (6) | No (4)  

swarnendu dutta  (10 years ago)

the answer is 3168

Is this solution Helpfull? Yes | No (2)  

kavitha.A  (9 years ago)

unit digit=2
ten digit=2 hundred digit=2 thousand digit=2
2+2*10+2*100+2*1000=2+20+200+2000=6000

Is this solution Helpfull? Yes | No (1)  

Neha Bhakat  (8 years ago)

1000+800=1800

Is this solution Helpfull? Yes | No   

riya singh  (8 years ago)

4 digit no contains 2 = total 4 digits no - 4 digits does not contain
9*10*10*10 - 8*9*9*9
3168

Is this solution Helpfull? Yes | No   

rahul kumar  (6 years ago)

The easiest way to do this:
Find the total number of 4 digit numbers. This is easy (from 1000 - 9999): 9000 numbers in all.
Find out how many of them do not contain the number 2.
There are 9 digits with the exception of 2. The second, third and fourth digit (from right to the left) make 9 x 9 x 9 = 729 possibilities.
There cannot be a 0 wither at the thousand's place so there are 8 possibilities.
Therefore, there are 8 x 729 = 5832 four-digit numbers that do not contain 2.
Thus, there are 9000 - 5832 = 3168 four-digit numbers that do contain the digit 2.

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