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Sum Inverse LCMs (Posted on 2008-10-03)

Each of P, Q, R, S and T are positive integers with P < Q < R < S < T. Determine the maximum value of the following expression.

[P, Q]^-1 + [Q, R]^-1 + [R, S]^-1 + [S, T]^-1

Note: [x, y] represents the LCM of x and y.

See The Solution Submitted by K Sengupta

Rating: 4.0000 (3 votes)

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looks obvious .......spoiler

| Comment 1 of 7

P, Q]^-1 + [Q, R]^-1 + [R, S]^-1 + [S, T]^-1

^{EQUALS 96/120=.8 FOR (1, 2,3,4,5)}

Posted by Ady TZIDON on 2008-10-03 12:36:47

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