What is the Number?

Question

It is a five-digit number.

If you place a 1 on the right of a five-digit number, the six digit number that is formed is 3 times the number formed when you place a 1 on the left of the five-digit number.

Answer 1

let be the number,

= 3<1abcde>
100000a + 10000b + 1000c +100d + 10e +1 = 300000 + 30000a + 3000b + 300c + 30d + 3e
70000a + 7000b + 700c + 70d + 7e = 299990 {rearranging}
10000a + 1000b + 100c + 10d + e = 42857 {divide everything by 7}
= 42857

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alternatively:
let be the number,
10 + 1 = 3(100000 +)
10 + 1 = 300000 + 3
7 = 299999
= 42857

Answer 2

Adding a 1 to the left hand side of a five digit number is like adding 100000 to it, and adding a 1 to the right hand side of a five digit number is like multiplying the number by 10 and then adding 1, so you know:

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

Answer 3

Let a, b, c, d, and e be the digits in this number.

10,000a + 1,000b + 100c + 10d + e is your number.

100,000a + 10,000b + 1,000c + 100d + 10e + 1 is your number with a 1 to the right of it.

100,000 + 10,000a + 1,000b + 100c + 10d + e is your number with a 1 to the left of it.

(100,000 + 10,000a + 1,000b + 100c + 10d + e) x 3 = 100,000a + 10,000b + 1,000c + 100d + 10e + 1

300,000 + 30,000a + 3,000b + 300c + 30d + 3e = 100,000a + 10,000b + 1,000c + 100d + 10e + 1

299,999 = 70,000a + 7,000b + 700c + 70d + 7e

Divide everything by 7:

42,857 = 10,000a + 1,000b + 100c + 10d + e

There's your answer.

Checking: 428,571 / 142,857 = 3

Answer 4

Five digits: a, b, c, d, e.

100000a + 10000b + 1000c + 100d + 10e + 1 = 3*[100000 + 10000a + 1000b + 100c + 10d + e]

Answer 5

it can't be
because if it is
say
1xxxxx
and
xxxxx1
number of digits is same
and it is the same number
then 1xxxxx*3 has to be
1xxxx(x has to be equal or more to 3)
ie..the digit inthe units place
has to be 3 or more than 3
and since digits being the same
you can't achieve this task

Answer 6

(10X + 1) = 3*(100000 + X)

10X + 1 = 300000 + 3X
7X = 299999
X = 42857