Posted by **James101** on Thursday, August 21, 2008 at 3:48am.

91 5-digit number are written on the board, how do u PROVE that there are 3 numbers on the board that the sum of the digits are equal?

- urgent maths -
**drwls**, Thursday, August 21, 2008 at 7:24am
The possible digit sums, for five-digit numbers, ranges from 1 (for 10000) to 45 (for 99999) That makes 45 possibilities. With 90 numbers selected, the least possible number of times any sum occurs is two, when each sum occurs twice. When you pick a 91st number, it has to be a third time for one of them.

- urgent maths -
**molly**, Thursday, August 21, 2008 at 10:17am
12

## Answer this Question

## Related Questions

- Maths - What are 3 5-digit numbers that have the sum of their digits equal? Is ...
- maths - Find the sum of all 3-digit positive numbers N that satisfy the ...
- maths - 91 five-digit numbers are written on a blackboard. Prove that one can ...
- maths- urgent - a) Forming the smallest six digit number with different digits...
- algebra - 2. The sum of both digits, of either of two two-digit numbers, in ...
- math - Prove that , if the difference between a three digit number in the form ...
- math - You have 2 digits, 2 numbers, reverse digits and 54 if the difference and...
- Maths - A 5 digit number is written on a white board. Ron erases one of its ...
- MATH Trouble - I have no idea what this problem means: For how many two-digit ...
- math - While adding ten two-digit numbers the digits of one of the numbers were ...