Prove that there are infinitely many positive integers n wit
Prove that there are infinitely many positive integers n with the following two properties: All of the digits of n in base 10 are 1
Solution
Since, we have given to prove that there are infinite number of integers whose base is 10 is 1 but divisible by 49
suppose, let\'s assume 3 digit integers
three digit integer : a1b
100a+10+b=980(maximum 49 multiple in two digits)
100a +b =970....which is not possible because (a and b lies between 0 and 9)
let\'s take four digits
four digits number: ab1c
1000a+100b+10+c=9996..(maximum four digit number which is multiple of 49)
1000a+100b+c=9886
So, there can be various possible values of \'a\' and \'b\' and \'c\'
For example:
1519 is multiple of 49 ...whose 10th base is 1
1617 is multiple of 49 ...whose 10th base is 1
1715 is multiple of 49 ...whose 10th base is 1
and many more
Similarly , there can be various value is possible if we take five digit numbers
and in six digits numbers
Hence , there infinitely many positive integers n with the digits of n in base 10 are 1
