Maths Olympiad Prep

Library / /4 of 60

Number theory Difficulty 3.7 AMC 10/12 Find the answer South Africa

If 12x\frac{12}{x} is a natural number and xx is a natural number, how many possible values are there for xx?

Pick one

Solution

xx must be a divisor of 1212, and the possibilities are 11, 22, 33, 44, 66, 1212, which is 66 in all.

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 and solution reproduced as published; topic and difficulty added by this site.