self
Maths Puzzle
21!=510909x21y1709440000
Without calculating 21!, what are the digits marked x and y? explain.
Read Solution (Total 3)
-
- Sum of the digits should be divisble by 9
Sum of the digits is 52 so r is 2 so (x+y)mod9=2
Possibilities is (1,1) (2,0)
Also sum of the digits will be divisble 11
Since sum of the digits is 52 and x and y are at even and odd places
so (x-y)mod11--- R is minimum=3
So that rules out (x+y)mod9=2 and then it should be 11
Various possibilities of 11 (7,4),(9,2),(8,3)....
But 7-4=3
So digits are 7,4 - 12 years agoHelpfull: Yes(4) No(0)
- x=4 and y=7
because it should be divisible by 9 and 11.
check for divisibility of 9 and 11 and solve the two equations. - 12 years agoHelpfull: Yes(1) No(0)
- ans x=4 and y=7.because by put that value no.is completely divisible by 21.
- 12 years agoHelpfull: Yes(0) No(2)
self Other Question