# [SOLVED] Number pyramid

• Feb 4th 2009, 08:07 AM
andyboy179
[SOLVED] Number pyramid
Attachment 9976 on that the t =3 and i need to fill in the other numbers but i also need to know how to work it out if any 1 can help please post this is different but i need to know if the top number is 42 what is T thank you

EDIT by Jhevon: Apparently the question was something like this.

Given that the number in the top box is 42, and that the number in each box (that is not in the base) is given by the sum of the two boxes directly below it, find T.
• Feb 4th 2009, 08:45 AM
Soroban
Hello, Andy!

You didn't give us the rule for filling the boxes.
I will assume that it is an "additive" sequence . . .

Code:

                  * - - - *                   |  42  |               * - + - * - + - *               |      |      |           * - + - * - + - * - + - *           |      |      |      |       * - + - * - + - * - + - * - + - *       |  4  |  T  |  3  |  5  |       * - - - * - - - * - - - * - - - *

Assuming that each number is the sum of the two numbers below it,
. . we have this pyramid.
Code:

                  * - - - *                   |  42  |               * - + - * - + - *               | 2T+7  | T+11  |           * - + - * - + - * - + - *           |  T+4  |  T+3  |  8  |       * - + - * - + - * - + - * - + - *       |  4  |  T  |  3  |  5  |       * - - - * - - - * - - - * - - - *

The final "step" would be: . $(2T+7) + (T + 11) \:=\:42$

And we get: . $3T + 18 \:=\:42 \quad\Rightarrow\quad 3T \:=\:24 \quad\Rightarrow\quad\boxed{ T \:=\:8}$

• Feb 4th 2009, 09:09 AM
andyboy179
hi u said http://www.mathhelpforum.com/math-he...cae25646-1.gif

but t=3 so 2t=6 so 6+7 =13 and 3+11=14 so i dunno how u got 42
• Feb 4th 2009, 09:19 AM
Soroban
Hello, Andy!

You still didn't give us any rules!

I didn't understand the problem.
We're given that $T = 3$, right?

And we're suppose to fill in the pyramid (without knowing how) ?
. . and figure out the top number?

Good luck!
Code:

                  * - - - *                   |  ?  |               * - + - * - + - *               |  ?  |  ?  |           * - + - * - + - * - + - *           |  ?  |  ?  |  ?  |       * - + - * - + - * - + - * - + - *       |  4  |  3  |  3  |  5  |       * - - - * - - - * - - - * - - - *
• Feb 4th 2009, 09:25 AM
andyboy179
Quote:

Originally Posted by Soroban
Hello, Andy!

You still didn't give us any rules!

I didn't understand the problem.
We're given that $T = 3$, right?

And we're suppose to fill in the pyramid (without knowing how) ?
. . and figure out the top number?

Good luck!
Code:

                  * - - - *                   |  ?  |               * - + - * - + - *               |  ?  |  ?  |           * - + - * - + - * - + - *           |  ?  |  ?  |  ?  |       * - + - * - + - * - + - * - + - *       |  4  |  3  |  3  |  5  |       * - - - * - - - * - - - * - - - *

oh ye sorry u can only add
• Feb 4th 2009, 09:32 AM
princess_21
Quote:

Originally Posted by andyboy179
Attachment 9976 on that the t =3 and i need to fill in the other numbers but i also need to know how to work it out if any 1 can help please post this is different but i need to know if the top number is 42 what is T thank you

i tried a bit i got 27 at the top. not really sure bout it.(Thinking)

Code:

                   * - - - *                   |  27  |               * - + - * - + - *               |  13    |  14    |           * - + - * - + - * - + - *           |  7    |  6    |  8    |       * - + - * - + - * - + - * - + - *       |  4  |  3  |  3  |  5  |       * - - - * - - - * - - - * - - - *
• Feb 4th 2009, 09:33 AM
andyboy179
Quote:

Originally Posted by princess_21
i tried a bit i got 27 at the top. not really sure bout it.(Thinking)

ye thats what i got
• Feb 4th 2009, 09:36 AM
princess_21
Quote:

Originally Posted by andyboy179
ye thats what i got

so where do you get 42? is that the right answer?
• Feb 4th 2009, 09:39 AM
andyboy179
Quote:

Originally Posted by princess_21
so where do you get 42? is that the right answer?

know the first bit of what u said about 27 that was the first question

the second question was about the 42 the question is if the top number is 42 what will T=
• Feb 4th 2009, 09:50 AM
princess_21
Quote:

Originally Posted by andyboy179
know the first bit of what u said about 27 that was the first question

the second question was about the 42 the question is if the top number is 42 what will t=

t= 8

Code:

                  * - - - *                   |  42  |               * - + - * - + - *           |    23 |  19    |           * - + - * - + - * - + - *     |  12    |  11    |  8    |       * - + - * - + - * - + - * - + - *   |    4  |  8  |  3    |  5  |       * - - - * - - - * - - - * - - - *
• Feb 4th 2009, 10:06 AM
princess_21
i got a formula from that pyramid try putting variables there.

Code:

                  * - - - *                   |  42  |               * - + - * - + - *               |  d  |  e  |           * - + - * - + - * - + - *           |  b    |  c    |  8  |       * - + - * - + - * - + - * - + - *       |  4  |  a  |  3  |  5  |       * - - - * - - - * - - - * - - - *
4+a=b
a+3=c
c+8=e
b+c=d
d+e=42

$d+e=42$

$(b+c)+(c+8)=42$

$(4+a)+(a+3) +(a+3) +8 =42$

$3a+18=42$

$3a=24$

$a=8$
• Feb 4th 2009, 10:12 AM
princess_21
by the way Andy, I didn't realized that Soroban already answered your question.. t=8. you should thank him too.
• Feb 4th 2009, 11:13 AM
Soroban
Hello, andyboy179!

Quote:

The second question was about the 42
The question is: if the top number is 42, what will T equal?

That's the question I answered first! . . . Didn't you read my response?

• Feb 4th 2009, 11:50 AM
andyboy179
Quote:

Originally Posted by Soroban
Hello, andyboy179!

That's the question I answered first! . . . Didn't you read my response?

yes i did read ur response but i read it wrong i thought u were on about the first question sorry if i have offended u