For any integer k > 1, the term "length of an integer" refers to the number of positive prime factors, not necessarily distinct, whose product is equal to k. For example, if k = 24, the length of k is equal to 4, since 24 = 2 × 2 × 2 × 3. If x and y are positive integers such that x > 1, y > 1, and x + 3y < 1000, what is the maximum possible sum of the length of x and the length of y?
5
6
15
16
18.
OA after some discussion
Tough one- difficult to solve in 2 min
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- ankur.agrawal
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here we have a clue... not necessarly distinct... so maximum count can come if most factor are 2
Let x = 2^8 = y then x+3y = 4(2^8) ~=1000
So 8+8 = 16 ... we need a little less
IMO 15 is the answer
This is what all I got in <2min
Let x = 2^8 = y then x+3y = 4(2^8) ~=1000
So 8+8 = 16 ... we need a little less
IMO 15 is the answer
This is what all I got in <2min
Last edited by HSPA on Tue Mar 22, 2011 8:48 am, edited 1 time in total.