Question

What 5-digit number has the following features:

If we put the numeral 1 at the beginning, we get a number three times smaller than if we put the numeral 1 at the end of the number.

Answer 1

1**** = 10000 + ****
####1 = ####0 + 1

10000 + **** = 3(####) + 3
9997 = 3(####) - ****

lol i dunno why i used such a notation

Answer 2

that looks like a 4 digit number

Answer 3

its first digit is 3??

Answer 4

nope

Answer 5

6 or 9

Answer 6

there's a simple closed form expression that solves it

Answer 7

i give up:(

Answer 8

Using an easy equation:

3(100000 + x) = 10x+1

(Why? Well, adding 100000 puts a 1 at the front of a five-digit number, and multiplying by 10 and adding 1 puts a 1 at the end of a number)

Solving this gives:

10x+1 = 3(100000 + x)
10x+1 = 300000 + 3x
10x = 299999 + 3x
7x = 299999
x= 299999/7 = 42857

The answer is 42857.

Answer 9

why did you post it ????? -___-

Answer 10

no one else seeemd to be working on it

Answer 11

i was getting the concept :\

Answer 12

sorry!

Answer 13

lol it's alright :-)