Question

I have a question #11

Answer 1

These numbers are in BANKY GROUP.
16325,34721,12347,52163,90341,50341

These numbers are in NON-BANKY GROUP.
2564,12345,854,12635, 34325,45026

Which of these numbers is in BANKY GROUP
a.75401
b.13562
c.72341
d.83051

Answer 2

help me i've no idea how to do it

Answer 3

what the monkey is "banky group"? or is that irrelevant?

Answer 4

its just a group name. could be anything LOL

Answer 5

ok just looking at "nonbanky group" i am going to make a guess
looks like all of these have remainders of 8 when divided by 9
does that help?

Answer 6

That's the name of his bank.

Answer 7

oops no that was wrong, sorry

Answer 8

dang, i thought i had it. of the non-banky group all but 12345 give a remainder of 8, but this one gives 6. sorry.

Answer 9

wow and of "banky group" all give a remainder of 8! every one. can't just be a coincidence is it? do you have a clue? what kind of class is this for?

Answer 10

what about 50341?

Answer 11

ok i give up. clearly i am on the wrong track, but it is kind of odd that all (except those two, 50341 and 12345) have remainders of 8
hmmm

Answer 12

i agree it's odd

Answer 13

still would like a clue as to what kind of class this is, and maybe what question 10 was. any hint would help

Answer 14

I would say c.

Answer 15

and you wish to leave us in suspense?

Answer 16

it's correct! so plz explain

Answer 17

(also remainder 8, btw)

Answer 18

I don't think my justification is complete, but c. is the closest I got.

Answer 19

All numbers in the banky group are of the form \(a_1a_2a_3a_4a_5\), with \(a_1\) odd and \(a_2\) even. Add to that 4 out of the six numbers of the group are primes, while none of the numbers in the other group is prime. Only 72341 is in that given form and prime.

Answer 20

4 out of 6 are prime? i mean i believe you, but that seems like an odd reason to pick c because it is prime

Answer 21

yeah, that's why I said it's not complete :D

Answer 22

but what is wrong with just the "even odd" stuff? looks good to me

Answer 23

Ok, I got. Ignore that. But keep the fact that none of the numbers on the other group is prime.

Answer 24

So, we can say that 72341 is not in group 2. It's the only number in that form, so it's the only choice.

Answer 25

c is the only one that has that "even-odd" pattern so maybe that is the complete solution

Answer 26

But there are number on the other group that has that same form, I think being prime has to be taken under consideration.

Answer 27

oh yeah you are right.

Answer 28

:D