Maths Olympiad Prep

Library / /4 of 129

Algebra Difficulty 3.6 AMC 10/12 Find the answer Slovenia

How many pairs (m,n)(m, n) of positive integers satisfy the condition 3m+2n=1\frac{3}{m} + \frac{2}{n} = 1?

Pick one

Solution

Clearly m>3m > 3 and n>2n > 2. Since nn decreases as mm increases nn, we see that the only possible solutions are (m,n){(4,8),(5,5),(6,4),(9,3)}(m, n) \in \{(4, 8), (5, 5), (6, 4), (9, 3)\}.

Want a route through all this instead of an archive? The track puts 2,000 problems in a working order, from AMC 10 level to the IMO shortlist.

Source: MathNet, licensed CC-BY-4.0. Statement reproduced verbatim; metadata (topic, difficulty) added by this project.