MathDB
2018 Individual #22

Source:

January 13, 2023
2018 Individual

Problem Statement

Country AA uses a currency known as the shell. The nation uses only two coins, each worth a whole number of shells. The largest amount of shell not obtainable using a combination of these two coins is 215215. Find the number of possible pairs of values these two coins could have. (a value of 1515 and 44 is the same as having a 44 and 1515)
<spanclass=latexbold>(A)</span>6<spanclass=latexbold>(B)</span>7<spanclass=latexbold>(C)</span>8<spanclass=latexbold>(D)</span>9<spanclass=latexbold>(E)</span>10<span class='latex-bold'>(A) </span> 6\qquad<span class='latex-bold'>(B) </span> 7\qquad<span class='latex-bold'>(C) </span> 8\qquad<span class='latex-bold'>(D) </span> 9\qquad<span class='latex-bold'>(E) </span> 10