A mathematical question for you

[scooterscot]

Easy

(n digits)9
x 4
9(n-1 digits)6


So the hundred's digit is 6. Continue to get 230769

And they have to do that without a calculator? Jeepers.

[WTFH]

Easy

(n digits)9
x 4
9(n-1 digits)6


So the tens digit is 6. Continue to get 230769

FTFY

[chopper]

Ask 10 different computer people, get 10 different mechanisms to find the answer. Quick, crufty, lazy perl method:

#/usr/bin/perl
my $special = 9;
my $boo = 0;
while ($boo == 0) {
my $new = $special * 4;
my $trans = $special;
chop $trans;
$trans = "9$trans";
if ($new == $trans) {
print "$special\n";
$boo = 1;
} else {
$special += 10;
}
}

$perl number
230769

Fairly sure this is a difficult one for those 10/11 year olds.

[ChimpMaster]

Easy

(n digits)9
x 4
9(n-1 digits)6


So the tens digit is 6. Continue to get 230769

FTFY

Still involves a fair amount of guesswork or manual counting though! I am shocked that this was in an 11+ paper

[Old Greg]

Obviously, just it wasnae specific.

What base?

[scooterscot]

yes

[WTFH]

Still involves a fair amount of guesswork or manual counting though! I am shocked that this was in an 11+ paper

Yup, too hard for me. I was going through it in excel randomly. I then tried to break it down as follows:
The first two digits must be 22, 23 or 24 (less than 22 will start with 8, more than 24 will give you a 1)
The second to last digit is a 6 (4x9 = 36)
Getting the ones in between was the guesswork bit

[DimPrawn]

God you lot are thick cretins.



QED, it's nuffink. Do I win a prize?

[sasguru]

Gah missed this.
There's no guesswork to it.
Once you've figured out the 10s digit is 6, you can keep going, multiplying by 4 till you get the answer.

[MarillionFan]

God you lot are thick cretins.



QED, it's nuffink. Do I win a prize?

That should be a 26 half way down, not 28.