Question 15
Bill wants to write a set of pairwise distinct positive integers on the board, ensuring that each number is divisible by at most one other number on the board.
(1)
Prove that Bill can write 14 numbers on the board.
(2)
Prove that Bill cannot write 15 numbers on the board.
(1)
Prove that Bill can write 14 numbers on the board.
(2)
Prove that Bill cannot write 15 numbers on the board.