numbers from 1-31
2006-12-26 16:53:16 · 6 answers · asked by HIGH low 2 in Science & Mathematics ➔ Mathematics
I wish I had a good way to figure it out, but just looking at a list of them, it appears that 15 and 21 fit the bill. 21 - 15 = 6, 21 + 15 = 36.
2006-12-26 16:58:36 · answer #1 · answered by Jim Burnell 6 · 0⤊ 0⤋
Your answer is most certainly 15, 15 and 21 are the only 2 triangular numbers that fit all your conditions. I noticed that someone said 9 and 6 but 9 is not a triangular number.
2006-12-27 05:05:40 · answer #2 · answered by superpsychicman 2 · 0⤊ 0⤋
The smaller number is 15.
The larger number is 21.
21 - 15 = 6 a triangular number
21 + 15 = 36 a triangular number
2006-12-27 01:26:00 · answer #3 · answered by Northstar 7 · 0⤊ 0⤋
Same here,
This is all I got:
15, 21 >>> The two numbers, 15 being the answer
n representing the nth tri number, the larger one
n(n+1)/2 + (n+1)(n+2)/2 = (n+1)(2n+2)/2 = (n+1)^2
n(n+1)/2 - (n-1)(n)/2 = (2n)/2 = n
The only way I see it is to brute force the question until you get an answer by plugging in points, until they work. It shouldn't be too bad for a restricted problem like this.
2006-12-27 01:09:53 · answer #4 · answered by AibohphobiA 4 · 0⤊ 0⤋
I was trying also to figure out an analytical way, but the solution is so simple looking at the first triangular numbers.
I'm completely agree with the first answer.
2006-12-27 01:06:28 · answer #5 · answered by j_orduna 2 · 0⤊ 0⤋
Ans. is 9 & 6
9+6=15,
9-6=3
2006-12-27 01:10:39 · answer #6 · answered by Anonymous · 0⤊ 1⤋