# Thread: Challenge! What is X?

1. ## Challenge! What is X?

Rallods in Rednow Land

The challenge quiz:

The law on how tellers in the Central Bank of Haetaque should work is very strict. When there is a request to hand over money, a teller must first take notes from the sack containing notes of size 3 rallods only and then take notes from the sack with notes of size 5 rallods only. The teller cannot then come back to the sack with 3 rallods notes but he or she can take as many notes from either sack as he or she wishes provided there is at least one note taken from each sack.
One day, a customer came to the Central Bank and told a teller that he wished to withdraw X rallods from his account. After a while, the teller figured out how she should act to give the customer the exact amount he requested but she also discovered that there was ony one way she could do this. What is X? Find all possible solutions.

2. ## Re: Challenge! What is X?

Hey lolyland.

Can you show us what you have tried? Have you been able to take the question and get some mathematical equations or inequalities?

Getting the equations is half the battle: once you have these the rest is just math and algebra.

3. ## Re: Challenge! What is X?

Hi chiro!

Actually I have been struggling to extract any equations. It is a toughie indeed!!

4. ## Re: Challenge! What is X?

Hint: Consider that you have two variables, one for the 3 rods and one for the 5 rods.

You will need to solve an equation 3x + 5y = N where N is the amount of rallods you need, x is the number of chunks taken from the 3-rallod bag and y is the size of chunks taken from the y-rallod bag.

We also assume that y is not a multiple of 3, but technically can be a multiple of 5.

See if you can use this information, or if you have other questions then ask.

5. ## Re: Challenge! What is X?

Thanks but I'm so lost. Sorry

6. ## Re: Challenge! What is X?

Do you know any number theory?

7. ## Re: Challenge! What is X?

number theory??
I feel so helpless. I am sincerely sorry about looking so idiotic chiro!

8. ## Re: Challenge! What is X?

Number theory is just a fancy way of studying relationships for whole numbers.

Take a look at linear diophantine equations and this:

LINEAR DIOPHANTINE EQUATIONS

9. ## Re: Challenge! What is X?

Ok thanks... So what what would I be doing with the equations of 3x +5y = N

10. ## Re: Challenge! What is X?

You are solving for whole positive numbers x and y given a value of N (your total deposit of rallods) noting that x is larger than y.