Solving a Math Problem: Number Interchange & 9 More

  • Thread starter Thread starter vepore2
  • Start date Start date
AI Thread Summary
The discussion revolves around a math problem involving a two-digit number where interchanging the digits results in a number that is 9 greater than the original. The equations derived from the problem indicate that the second digit is one more than the first digit, leading to the conclusion that multiple solutions exist. The participant concludes that the number 12 is one valid solution, but acknowledges that any number where the second digit is one more than the first (like 23, 34, etc.) also satisfies the conditions. This indicates that the problem is underdetermined, as there are infinitely many valid combinations. Ultimately, the key takeaway is that there isn't a unique solution, but rather a set of numbers that fit the criteria.
vepore2
Messages
4
Reaction score
0
Let us consider a two digit number. If the digits are interchanged, the new number is 9 more than the original number. The second digit of the original number is one more than the first digit. Find the number.
Let x be the first digit and y be the second digit

(10y + x) - (10x +y) = 9
and
y -x =1

(10y + x) - (10x +y) = 9
9y -9x = 9
y - x = 1

I find out that both equations are the same does that mean that there isn't enough information or have I done something wrong?
From messing around I find the number is 12
 
Mathematics news on Phys.org
It is underdetermined. Any number where y-x = 1 will work.
 
U can't find two separate value OR unique Values

Generally the digits will be x at units place and 1+x at ten's digit and 0<x<9
 
What do you mean "From messing around I find the number is 12"? Just how messy were you? Did you think about 23? 34? 45? 56? 67? 89? All those number have exactly the properties you require. (Of course, that is exactly what Moose352 said: "Any number where y-x = 1 will work."
 

Thread 'Non-orthogonal bases'

Suppose ,instead of the usual x,y coordinate system with an I basis vector along the x -axis and a corresponding j basis vector along the y-axis we instead have a different pair of basis vectors ,call them e and f along their respective axes. I have seen that this is an important subject in maths My question is what physical applications does such a model apply to? I am asking here because I have devoted quite a lot of time in the past to understanding convectors and the dual...
View full post »

Thread 'What Exactly is Dirac’s Delta Function? - Insight'

Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
View full post »

Similar threads

MHB Simultaneous equations number problem
Replies
1
Views
1K
B How to pick some numbers out of 13 integers, by a 4 digits code
Replies
4
Views
2K
MHB How Many Numbers Less Than 1000 Divisible by 5 Are Formed Using Unique Digits?
Replies
1
Views
1K
B How Do You Solve This Mysterious Number Puzzle?
Replies
10
Views
2K
B Natural Numbers contain all the Primes
Replies
24
Views
3K
MHB Recreational Number Theory, Unsolved Problem
Replies
1
Views
2K
MHB Possible combinations for six digit license plates, numbers 0-9 and letters a-z.
Replies
1
Views
6K
I Alternating Harmonic Numbers are cool, spread the word!
Replies
4
Views
2K
MHB What is the last odd digit in the factorial sequence?
Replies
1
Views
2K
MHB Find the Two-Digit Number: Exceeds by 4 and 1 Less Than Twice the Units Digit
Replies
3
Views
3K

Hot Threads

Recent Insights

Back
Top