Very nice, Melody......in a slightly different manner.....the sum of the first n integers =
[n (n + 1)] / 2 <= 250
n^2 + n <= 500
n^2 + n - 500 <= 0
On the graph here : https://www.desmos.com/calculator/ajecyupfie , the largest positve root = about 21.87....so, we can take the floor of 21.87 as the answer = 21 rows
Hi Solveit and Guest ,
250 toothpicks how many rows (pyramid) could you make
1 on the top
2 on the next row
3 on the next row etc
1+2+3+4+......+n≤250
1+2+3+....+n
is the sum of an AP
a=1d=1Sn=n2(a+L)Sn=n2(1+n)son2(1+n)≤250n(1+n)≤500n2+n−500≤0Solve for 0n=−1±√1+20002n=−1±√20012n is not negativen=−1+√20012n=21.8so there can be 21 rows
231 toothpickswill be used andthere will be 19 left over :)
Very nice, Melody......in a slightly different manner.....the sum of the first n integers =
[n (n + 1)] / 2 <= 250
n^2 + n <= 500
n^2 + n - 500 <= 0
On the graph here : https://www.desmos.com/calculator/ajecyupfie , the largest positve root = about 21.87....so, we can take the floor of 21.87 as the answer = 21 rows
Suppose the toothpicks are arranged as follows (i.e. 3 per row; after all they are long and thin!):
Then you get 12 rows with 16 left over.
That is great Alan. I bet that is exactly what was intended.
I did think my pyramid was very weighed down (flattened). Maybe with time. LOL
Then again maybe my toothpicks were standing upright. That would have made a very tall skinny 'tower' I guess. :)