+0  
 
0
90
1
avatar+205 

hiiii

 Jun 13, 2020
edited by qwertyuiopasdfghjkl  Jun 20, 2020
 #1
avatar+8205 
0

That means ab = 2p.

 

Two integers whose product is a semiprime. That means (a, b) = (2, p) or (p, 2) or (1, 2p) or (2p, 1).

 

Therefore the number of ordered pair is 4n, where n is the number of prime number less than 100.

 

You can finish it by counting the number of primes smaller than 100. 

 Jun 13, 2020

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