Elitmus
Exam
Numerical Ability
Number System
a 9 digit number consist of 1 through 9 (eg 123456789)is divisible by 11.what is the difference between the sum of the alternate numbers.
dnt knw exact questn
Read Solution (Total 12)
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- consist a no.consisting of digits through 1 to 9
let x,y be sum of even,odd places of number
so x+y=1+2+3+...+9=9*10/2=45
x+y=45(always)
given no. is divisible by 11
so x-y=0 or multiple of 11
x-y=0,11,22,33,44
x+y=45,x-y=0, x=y=45/2(not possible as its integrs sum )
x+y=45,x-y=11, x=28,y=17
x+y=45,x-y=22, x=67/2(not possible)
x+y=45,x-y=33, x=39,y=6(not possible as 9+8+7+6+5+4=39 )
check by example 192837645
so difference between the sum of the alternate numbers must be 11 only
ans 11 - 11 years agoHelpfull: Yes(47) No(2)
- It is either 0 or 11. Note: For a number to be divisible by 11, the difference between the sum of its alternate numbers is always 0 or 11.
- 11 years agoHelpfull: Yes(8) No(3)
- Ans is 11.
coz let x and y be sum of numbers in odd and even places respectively.
then we know x+y=45(1+2+3..+9), x-y= multiple of 11 - 11 years agoHelpfull: Yes(6) No(0)
- It wud b either 0 or 11.According to divisibility test of 11.
- 11 years agoHelpfull: Yes(1) No(2)
- Difference will be either 0 or 11.
- 11 years agoHelpfull: Yes(1) No(0)
- i think that it is only divisible by 11 .....because we have not tell any thing about 22 and 33
- 11 years agoHelpfull: Yes(0) No(1)
- visit this for solution http://www.onlineadhyayana.com/ elitmus section...:)
- 11 years agoHelpfull: Yes(0) No(6)
- ans should be zero.
as it is the prpoerty of 11 , to any no, divisible by 11 . the sum of even and odd integers i.e alternate digits sum must be zero . - 11 years agoHelpfull: Yes(0) No(0)
- either 0 or 11
- 11 years agoHelpfull: Yes(0) No(0)
- what rakesh aays was not true for all the no's .Now,consider no 324157689 we dont get difference b/w them is 9
- 11 years agoHelpfull: Yes(0) No(5)
- @ Rakesh thanks ....
- 10 years agoHelpfull: Yes(0) No(1)
- either 0 or 11
- 9 years agoHelpfull: Yes(0) No(0)
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