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MathNet 2000 — Math Olympiad Vault Question 161

Math Olympiad Vault · MathNet 2000 — Math Olympiad Vault

Question 161

In a regular tetrahedron with vertices $A,B,C,D$, let $P,Q$ be the centers of the two faces sharing edge $AB$. What is the ratio of the volume of the original tetrahedron to the volume of tetrahedron $ABPQ$?


Problem:

Let $n$ be the smallest positive integer greater than $200$ that can be written as a sum of 5 consecutive integers, as a sum of 6 consecutive integers, and as a sum of 7 consecutive integers. What is $n$?