+0  
 
0
32
4
avatar+660 

Syd chooses two different primes, both of which are greater than 10, and multiplies them. The resulting product is less than 400. How many different products could Syd have ended up with?

 Sep 22, 2023
 #3
avatar+36921 
+1

The lowest prime in the list would be 11     400/11 = 36.4    so the biggest prime int the list will be 31    11*31 = 341

   so from 11 to 31   the list of primes is  11  13  17  19   23  29  31    

           11 x the other 6   is 6 possibilities 

               13 x  17, 19,23,29    is 4 more possibles

                      17 x 19,  23   is two more 

                          and that is all          12 possible products 

 Sep 22, 2023

2 Online Users

avatar
avatar