Find the Smallest of A and B: $A-B=98$ with Multiple of 19 Digit-sum

  • MHB
  • Thread starter Albert1
  • Start date
  • Tags
    Multiple
In summary, the equation for finding the smallest value of A and B if their difference is 98 and their digit-sum is a multiple of 19 is A = 98 + 19n and B = 19n, where n is any positive integer. This equation gives the smallest possible values for A and B because the digit-sum of B is the smallest possible value and the digit-sum of A will be larger but still a multiple of 19. It can work for any other difference that is a multiple of 19 and even if the difference is negative. However, it cannot be used to find the smallest values for any two numbers with a given difference and digit-sum unless the conditions of the equation are met.
  • #1
Albert1
1,221
0
$(1)A,B \in N,A-B=98$

(2)All the digit-sum of $A$ and $B$ are multiple of 19

please find the smallest of $A\,\, and \,\, B$
 
Last edited:
Mathematics news on Phys.org
  • #2
Albert said:
$(1)A,B \in N,A-B=98$

(2)All the digit-sum of $A$ and $B$ are multiple of 19

please find the smallest of $A\,\, and \,\, B$

we have B mod 9 = x if sum of digits of a = 19 x
so (B + 98) mod 9 = x+ 8
for A and B both divisible by 19 we should have
so A Mod 9 is one less than B mod 9 with the proviso that b mod 9 = 0 => a mod 9 = 8

so smallest possible candidate should be digit sum of B= 38 and A = 19 as digit sum of B mod 9 is 1 more than digit sum of A mod 9
Smallest possible B = 29999 giving A = 30097 and it meets criteria
so B = 29999, A = 30097 is smallest solution,
 
Last edited:

FAQ: Find the Smallest of A and B: $A-B=98$ with Multiple of 19 Digit-sum

What is the equation for finding the smallest value of A and B if their difference is 98 and their digit-sum is a multiple of 19?

The equation for finding the smallest value of A and B is A = 98 + 19n and B = 19n, where n is any positive integer. This equation satisfies the condition that A-B=98 and their digit-sum is a multiple of 19.

How can we prove that this equation gives the smallest possible values for A and B?

We can prove this by considering the properties of the digit-sum. The digit-sum of a number will always be less than or equal to the number itself. Therefore, by setting B = 19n, we are ensuring that the digit-sum of B is the smallest possible value. Since A is defined as A = 98 + 19n, the digit-sum of A will be larger than the digit-sum of B, but still a multiple of 19. Hence, this equation gives the smallest possible values for A and B.

Can this equation work for any other difference apart from 98?

Yes, this equation can work for any difference that is a multiple of 19. For example, if the difference is 38, the equation will be A = 38 + 19n and B = 19n. The digit-sum of A and B will still be a multiple of 19.

What happens if we use a negative difference in the equation?

If we use a negative difference, the equation will still hold true. However, the values of A and B will be negative as well. For example, if the difference is -98, the equation will be A = -98 + 19n and B = 19n. The digit-sum of A and B will still be a multiple of 19.

Can we use this equation to find the smallest values for any two numbers with a given difference and digit-sum?

No, this equation only works when the difference is a multiple of 19 and the digit-sum is also a multiple of 19. If these conditions are not met, we cannot use this equation to find the smallest values for A and B.

Similar threads

Replies
2
Views
2K
Replies
7
Views
1K
Replies
7
Views
1K
Replies
2
Views
1K
Replies
1
Views
1K
Replies
1
Views
2K
Replies
1
Views
979
Replies
2
Views
2K
Back
Top