Number Theory
Linear Diophantine Equations
- the first (in other words, the left-most) digit is one-third the second digit,
- the third digit is the sum of the first and second digits,
- and the last digit is three times the second digit?
by
Christian Daang
Find the two digit positive integer that is equal to:
- one more than eight times the sum of its digits
AND
- two more than the product of 13 and the positive difference between its digits.
by
Jai Gupta
\[ \large{\begin{array}{ccccccc} && & & \color{blue}X& \color{blue}X & \color{blue}X&\color{blue}X\\ && & & \color{green}Y& \color{green}Y & \color{green}Y&\color{green}Y\\ +&& & & \color{red}Z& \color{red}Z & \color{red}Z&\color{red}Z\\ \hline & & & \color{green}Y& \color{blue}X& \color{blue}X & \color{blue}X&\color{red}Z\\ \hline \end{array}} \]
If \(\color{blue}X\), \( \color{green}Y\) and \(\color{red}Z\) are distinct digits in the sum above, then find \(\color{red}Z\).
by
Victor Paes Plinio
Hint: Don't try to list all of the possibilities!
by
Eli Ross
Gummy bears come in packs of 6 and 9. Is there a combination of these packs which gives a total of exactly 100 gummy bears?
by
Clara Blackstone