How many 5 digit multiples of 11 are there, if the digits 3,4,5,6,7 are in some order. I.e. the number is formed by these 5 digits without repetition.
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
N = a b c d e
To be divisible by it should satisfy ( a + c + e ) − ( b + d ) = 1 1 k
As, ( 7 + 6 + 5 ) − ( 3 + 4 ) = 1 1
So, k can be 0 , 1
Case(1) : k = 0
a + c + e = b + d .These all numbers are in A.P. so sum of three can not be equal to sum of two.
Case(2): a + c + e − b − d = 1 1
This has only one solution i.e. ( a , c , e ) can be 5 , 6 , 7 and ( b , d ) can be ( 3 , 4 )
Taking permutations of these numbers total number of N is = 3 ! × 2 ! = 1 2