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?
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