Number of Possible Sums with 1-15 Cards

  • Context: MHB 
  • Thread starter Thread starter WMDhamnekar
  • Start date Start date
  • Tags Tags
    Cards Sums
Click For Summary

Discussion Overview

The discussion revolves around determining the number of distinct sums that can be formed using a set of cards with specified values. Participants are exploring the implications of using different combinations of these cards, with a focus on whether the provided answer of 143 distinct sums is accurate. The scope includes combinatorial reasoning and the exploration of distinct sums based on the number of cards used.

Discussion Character

  • Exploratory
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant argues that at least two numbers are needed for any sum, suggesting that the calculation of distinct sums should be based on combinations of two or more cards.
  • Another participant points out that while combinations of cards can be calculated, they may not yield distinct sums, indicating a potential flaw in the initial reasoning.
  • A participant mentions computing 141 distinct sums and questions which two sums may have been omitted to reach the provided answer of 143.
  • There is a mention of a formula for calculating distinct sums, but no consensus on its application or correctness in this context.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the number of distinct sums. There are competing views on the validity of the answer 143 and the methodology for calculating distinct sums.

Contextual Notes

Participants express uncertainty regarding the distinctness of sums derived from combinations and the implications of the problem's constraints. The discussion highlights the complexity of combinatorial reasoning in this context.

WMDhamnekar
MHB
Messages
378
Reaction score
30
There are 8 cards with number 10 on them, 5 cards with number 100 on them and 2 cards with number 500 on them. How many distinct sums are possible using from 1 to all of the 15 cards?Answer given is 143. But my logic is for any sum, at least 2 numbers are needed. So, there are $\binom{15} {2} + \binom{15}{3}+...\binom{15}{15} $ distinct sums. So, I think answer 143 is wrong.
What is your opinion?
 
Mathematics news on Phys.org
\begin{pmatrix}15 \\ 2 \end{pmatrix} is the number of sums of two of the numbers, \begin{pmatrix}15 \\ 3 \end{pmatrix} is the number of sums of three of the numbers, etc. But they won't be distinct sums.
 
Dhamnekar Winod said:
There are 8 cards with number 10 on them, 5 cards with number 100 on them and 2 cards with number 500 on them. How many distinct sums are possible using from 1 to all of the 15 cards?Answer given is 143. But my logic is for any sum, at least 2 numbers are needed. So, there are $\binom{15} {2} + \binom{15}{3}+...\binom{15}{15} $ distinct sums. So, I think answer 143 is wrong.
What is your opinion?

The directions clearly state from 1 to 15, so their solution is based on that premise.
 
CountryBoy said:
\begin{pmatrix}15 \\ 2 \end{pmatrix} is the number of sums of two of the numbers, \begin{pmatrix}15 \\ 3 \end{pmatrix} is the number of sums of three of the numbers, etc. But they won't be distinct sums.

Hello,

I have computed 141 distinct sums. But the answer is 143. Which 2 distinct sums i omitted, would you tell me? Is the answer 143 wrong? All the 141 distinct sums are

20,30,40,50,60,70,80,110,120,130,140,150,160,170,180,200,210,220,230,240,250,260,270,280,300,310,320,330,340,350,360,370,380,400,410,420,430,440,450,460,470,480,500,510,520,530,540,550,560,570,580,600,610,620,630,640,650,660,670,680,700,710,720,730,740,750,760,770,780,800,810,820,830,840,850,860,870,880,900,910,920,930,940,950,960,970,980,1000,1010,1020,1030,1040,1050,1060,1070,1080,1100,1110,1120,1130,1140,1150,1160,1170,1180,1200,1210,1220,1230,1240,1250,1260,1270,1280,1300,1310,1320,1330,1340,1350,1360,1370,1380,1400,1410,1420,1430,1440,1450,1460,1470,1480,1500,1510,1520,1530,1540,1550,1560,1570,1580.


I know one formula $\binom{r+n-1}{r-n+1}$ which computes distinct sums, where n=cells and r= balls. How to use that here? Or is there any other formula?
 
Last edited:

Similar threads

  • · Replies 9 ·
Replies
9
Views
3K
Replies
2
Views
3K
  • · Replies 9 ·
Replies
9
Views
2K
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 68 ·
3
Replies
68
Views
12K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 5 ·
Replies
5
Views
2K