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jmc

number theory senior

Problem

What is the largest integer less than that has a remainder of when divided by a remainder of when divided by and a remainder of when divided by ?
Solution
We want a remainder of when divided by both and . The least common multiple of and is . We add to the number such that the remainder would be when divided by and so we get . However, that does not give a remainder of when divided by , so we add more s until we get a value that works. We get that gives a remainder of when divided by .

Since we want the largest integer less than 2010, we keep adding the least common multiple of , , and until we go over. The least common multiple is . We add it to to get , adding it again would give a value greater than , so our answer is .
Final answer
1440