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Find the smallest natural number n which has the following properties:

a) Its decimal representation has six as the last digit.
b) If the last digit 6 is erased and placed in the front of the remaining digits, the resulting number is 4 times as large as the original number n.

2006-08-19 03:14:52 · 20 answers · asked by Anonymous in Science & Mathematics Mathematics

20 answers

I will use the following:
n= your number; n= .....6
x= the number you obtain in case b; x= 4*n = 6.....
and I will wright the beginning and the ending of them, till I will get the final digit of the beginning to be the same as the first digit of the ending

Think about what happens if you try to multiply a number that has the last digit 6 with four,or if you try to divide a number that begins with 6 to 4.....

n= 1....6
x= 61....4

n= 15....46
x= 615....84

n=153....846
x= 6153.....384

so x=615384.......and n=153846

Let's check if x= 4*n
153846 *4 = 615384.......so it's correct

2006-08-19 04:44:44 · answer #1 · answered by Delfina 3 · 1 0

1

2006-08-19 10:19:07 · answer #2 · answered by gallow 5 · 0 1

Let a be the number formed by every digit except the last. Then n=10a+6 and 4n=6*10^d+a, where d is the number of digits in a. This gives us the equation 6*10^d+a=4(10a+6). Solving for a, we get 6*10^d+a=40a+24 → 39a = 6*10^d-24 → a=(6*10^d-24)/39. All that remains is to try natural values of d until we get a natural number. Thus:

d=1, a=12/13
d=2, a=192/13
d=3, a=1992/13
d=4, a=19992/13
d=5, a=15384

Thus n=153846, and 4n=615384, as required.

2006-08-19 11:03:19 · answer #3 · answered by Pascal 7 · 0 0

Let A represent the 5-digit string (other than the 6).

The original number is 10A + 6, and
the new number is 600000 + A.

4(10A + 6) = 600000 + A
40A + 24 = 600000 + A
39A = 599976
A = 599976 / 39 = 15384

The original number is 153846.

2006-08-19 12:50:03 · answer #4 · answered by Louise 5 · 0 0

X = 6 * 10 ^0 + A1*10^1 + ..... + An*10^n

4X = A1*10^0 + A2*10^1 + ... An*10^n-1 + 6*10^n

A1 = 0,2,4 because 4X is divisible by 4.

6 + A1 = 0 or 5 because 5X is divisible by 5.
thus A1 = 4
chechk the numbers 46,64 for the required properties

repeat this process until the correct number is found.

2006-08-19 10:50:42 · answer #5 · answered by gjmb1960 7 · 0 0

7

2006-08-19 10:18:56 · answer #6 · answered by Level 3 3 · 0 1

666

2006-08-19 10:20:12 · answer #7 · answered by Anonymous · 0 1

as u represented it as decimal then it cannot be natural number.. it will be real number i think

2006-08-19 10:33:07 · answer #8 · answered by Prakash 4 · 0 1

is this an easy answer

sorry cant do that im in a hurry

2006-08-19 10:53:25 · answer #9 · answered by Anonymous · 0 0

This reminds me of this one time at band camp.. yuo can take it from there

2006-08-19 10:19:23 · answer #10 · answered by kangaroo 3 · 0 1

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