Latest Elitmus Aptitude Question SOLUTION: How many odd numbers are possible between 1 to 10000? find out the number of odd number of digits?

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(#M40156198) ELITMUS Numerical Ability question Number System Keep an EYE

How many odd numbers are possible between 1 to 10000? find out the number of odd number of digits?

Asked In Elitmus Elakkiya Balasubramanian (8 years ago)

Unsolved Read Solution (18)

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Read Solution (18) :

Deepak 7  (8 years ago)

There are always one odd and one even no. And the question is odd no. Between 1 to 10000
So we have to find no. Between 1 to 10000 so we should not includes 1
10000/2 -1=4999 is the answer

Is this solution Helpfull? Yes (25) | No (3)  

Suhit  (8 years ago)

total odd no - 5000
no of odd digits are
1- 10 = 5
11-20 - 14
21-30 - 5
31 - 40 = 14
41-50 = 5
51 - 60 = 14
61 - 70 = 5
71 - 80 = 14
81 - 90 = 5
91 - 99 = 14

1digit - 5
2digit - 45*2
3 digit- 450*3
4 digit - 4500*3
total - 14945

Is this solution Helpfull? Yes (11) | No (15)  

Avinash Kumar  (8 years ago)

a=1,d=2,
now, 1000=1+(n-1)2, 999=1+(n-1)2,n=998/2+1,n=1000/2
n=500

Is this solution Helpfull? Yes (7) | No (10)  

Manisha Choudhary  (7 years ago)

If you are considering 1 then Ans is 5000
If not then it is 4999

Is this solution Helpfull? Yes (6) | No (1)  

mohit  (8 years ago)

1digit - 5
2digit - 45*2
3 digit- 450*3
4 digit - 4500*3
total - 14945

Is this solution Helpfull? Yes (5) | No (15)  

garima gupta  (8 years ago)

last odd no will be 9999 so 9999=1+(n-1)2 (AP with d=2 and tn=9999)
n==5000 odd no's
second part :
no of odd number of digits .
1....9=9
100......999=900
10000
so total no of odd no of digits =9+900+1=910

Is this solution Helpfull? Yes (2) | No (3)  

abhishek  (7 years ago)

nos of odd numbers bw 1-10=5
nos of odd numbers bw 11-99 can be calculated as:
11, 13 , 15,....99 so 99=11+(n-1)2 .... therefore n =45.
similarly for 100-999 it will be 450
and for 1000-10000 it will be 4500.
So the total nos of odd numbers are 5+45+450+4500=5000

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

Aryan kashyap  (7 years ago)

number of terms n=(L-a)/d+1
n=(9999-1)/2+1=5000

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

palak tandon  (7 years ago)

l=a+(n-1)*d
1+3+5+...........+9999
9999=1+(n-1)2
9998/2=(n-1)
4999+1=n
n=5000

Is this solution Helpfull? Yes (2) | No (1)  

alka patel  (7 years ago)

First we have to find out how many odd no are there I.e.
10000/2=5000
Then next step is to find out the no of odd no which have odd no of digit
1: from 1 to 9 we have 5 odd no.
2: from 101 to 999 then we have--
999=101+(n-1)*2
n= 450
3: next term will start from 10001 but it is greater than 10000
So ans = 450+5= 455

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

kamakshi gupta  (7 years ago)

what should do for the 2nd part not being clear...
plz help

Is this solution Helpfull? Yes (1) | No   

jaya  (8 years ago)

suhit
in 4 digit -4500*4=18000

ans-19445

Is this solution Helpfull? Yes | No (6)  

dytort  (7 years ago)

4998 odd no. possible b/w 1 to 10000

total no of digits in odd no.s are 161500

total no. of odd digits in odd no.s are 17500

Is this solution Helpfull? Yes | No (3)  

atul pandey  (7 years ago)

it's very simple. the given question is seem to be an a.p. because odd numbers come alternatively.
that's why.
Solution:-
let the first term a=1, common difference d=2 last term l=9999
using formula Tn=a+(n-1)*d
9999=1+(n-1)*2
n=5000
so the number of odd digits will be 5000.

Is this solution Helpfull? Yes | No (2)  

shilpa  (7 years ago)

1 TO 10 there are 5 ODD NO.'S and 1 to 100 there are 25 odd digit no.
and 100 to 200 againly 25 odd digit no.
200 to 300 no. odd digit no.
300-400 againly 25
500-600 againly 25
700-800 againly 25
900-1000 aganily 25
such that 1 to 1000 there are 5 series each contain 25 odd digit no.'s so 1000 to 2000 also there are 5 series each contain 25 odd digit no. and 3000 to 4000 same thing will happen
so conclusion is that the total odd digit no. is 1 to 1000 numbers are 125
so 1 to 10000 number is = 125+125+125+125+125+125=750.

Is this solution Helpfull? Yes | No (3)  

sonal priyanka  (7 years ago)

The no of odd no between 1 and 10000 is-(10000÷2)-1=4999
and no of odd no of digits-:9+900+1=910

Is this solution Helpfull? Yes | No (4)  

sandeep  (7 years ago)

First question understand--- find out the number of odd number of digits means - digits are odd
odd digit - 1,3,5,7,9---total five digits--5 odd numbers
2 digits --- 5*5=25 ways
3 digits--- 5*5*5=125 ways
4 digits --5*5*5*5=625 ways
so 5+25+125+625= 780 numbers

Is this solution Helpfull? Yes | No   

shubham kumar maurya  (4 years ago)

there are odd no from 0-9{1,3,5,7,9}
1 digit no are =5
2 digit no are =5*5=25
3 digit no are=5*5*5=125
4 digit no are=5*5*5*5=625
total no are =5+25+125+625=780

Is this solution Helpfull? Yes | No   

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