Series

clandarkfire

Grammar Nazi

Posers and Puzzles

14 Oct 10 20:22

RevRSleeker

CerebrallyChallenged

Lyme BayChesil Beach

Joined: 09 Dec 06
Moves: 17848

06 Dec 10 22:11

So no, no idea how 117 relates there...sorry.

iamatiger

Joined: 26 Apr 03
Moves: 26771

07 Dec 10 08:47

I'm stuck too

FabianFnas

Joined: 11 Nov 05
Moves: 43938

07 Dec 10 11:54

1 edit

Originally posted by RevRSleeker
cubes of 1 through 4..the 5th, 5x5x5, 125 is the answer.

Both 117 and 125 is a possible answer, along with innumerous other numbers. It's the motivation for the answer that either is correct or incorrect.

mtthw

Joined: 07 Sep 05
Moves: 35068

07 Dec 10 12:28

Originally posted by RevRSleeker
cubes of 1 through 4..the 5th, 5x5x5, 125 is the answer.

125 is the obvious answer, yes. I found a different one. It's to do with the differences between terms.

~~Removed~~

07 Dec 10 14:17

Originally posted by mtthw
125 is the obvious answer, yes. I found a different one. It's to do with the differences between terms.

thanks for the hint

8-1 = 7 = 4th prime
27-8 = 19=8th prime
64-27= 37=16th prime

so the 5th term is 64+53 =117

pretty interesting!

RevRSleeker

CerebrallyChallenged

Lyme BayChesil Beach

Joined: 09 Dec 06
Moves: 17848

07 Dec 10 16:41

Originally posted by joe shmo
thanks for the hint

8-1 = 7 = 4th prime
27-8 = 19=8th prime
64-27= 37=16th prime

so the 5th term is 64+53 =117

pretty interesting!

That's good lateral thinking..I'm afraid, therefore, my future participation on this forum will obviously be very limited 😛

mtthw

Joined: 07 Sep 05
Moves: 35068

08 Dec 10 09:07

Originally posted by joe shmo
so the 5th term is 64+53 =117

That's right. As you can imagine, I was a bit irritated the teacher wouldn't accept the answer! (Though to be fair, I should have realised that pattern was more complicated than all the others we were being given).

iamatiger

Joined: 26 Apr 03
Moves: 26771

08 Dec 10 09:20

3 edits

Originally posted by joe shmo
thanks for the hint

8-1 = 7 = 4th prime
27-8 = 19=8th prime
64-27= 37=16th prime

so the 5th term is 64+53 =117

pretty interesting!

I think there was a small typo there:

8-1 = 7 = 4th prime
27-8 = 19=8th prime
64-27= 37=12th prime

and 53 is the sixteenth prime

But it is a very nice answer, congratulations!

~~Removed~~

08 Dec 10 13:11

Originally posted by iamatiger
I think there was a small typo there:

8-1 = 7 = 4th prime
27-8 = 19=8th prime
64-27= 37=[b]12th prime

and 53 is the sixteenth prime

But it is a very nice answer, congratulations![/b]

whoops...😉