## Where is the Party?

One day you meet your friend Alice enjoying a nice walk with her husband Bob and their son Carl. They are excited to see you and they invite you to their party.

Alice: Please, come to our party on Sunday at our place at 632 Elm St. in Watertown.

Bob: My wife likes exaggerating and multiplies every number she mentions by 2.

Carl: My dad compensates for my mom’s exaggerations and divides every number he mentions by 4.

Alice: Our son is not like us at all. He doesn’t multiply or divide. He just adds 8 to every number he mentions.

Where is the party?

Share:
## Rosario:

With a as Alice’s multiplicator and n as the house number I get:

n * 2(4-(8/a)) = 632

Only a=4 works out (632=2^3*79), so n=158.

10 May 2015, 12:41 pm## Chris Hills:

A multiplies by a

B divides by b

C adds 8

B says that a = 2

C says that b = 4

A says that c = 8

So a doesn’t equal 2, it equals 2 * b, so that when B divides that by b he says “a = 2”. Similarly b = 4 – c, and c = 8 / a.

a = 2b = 8 – 2c = 8 – 16 / a

a2 = 8a – 16

a2 – 8a + 16 = 0

(a – 4)2 = 0

a = 4

b = 2

c = 2

So the address is 632 / 4 = 158 Elm St.

12 May 2015, 5:48 pm## Chris Hills:

That should have said C adds c

12 May 2015, 5:49 pm## Konstantin Knop:

I changed last sentences (sorry my English

Alice: Please, come to our party on Sunday at our place at 632 Elm St. in Watertown.

Bob: My wife likes exaggerating and multiplies every number she mentions by 2.

Carl: My dad compensates for my mom’s exaggerations and divides every number he mentions by 4.

Alice: Our son is not like us at all. He doesn’t multiply or divide. He just adds __ to every number he mentions.

I: Sorry, Alice, I’m not listen what’s Carl adding number.

15 May 2015, 8:32 amAlice: Not a matter. Information is enough.

## tanyakh:

Konstantin,

This is great! The exact number that Carl uses is not needed.

You can say it like this:

I: Sorry, I didn’t hear Carl’s adding number.

15 May 2015, 4:27 pmAlice: It doesn’t matter. You have enough information to find our party.

## Albert and Bernard - Helix @ CSIRO:

[…] A different party brainteaser […]

22 May 2015, 2:04 am## Chris:

Konstantin and Tanya. Not true. If you don’t hear Alice say 8 then a cannot be calculated eg If Alice says 6 then a =2 and a=6 are both possible.

26 May 2015, 1:25 am## perlexed:

Question:

8 June 2015, 2:51 pmIf they’re such great friends, shouldn’t they know each other’s address?