Explanation:
OK, 'Brainless'.... the triangle side length rule states that any two sides of a triangle must sum to greater than the remaining side length...
42 + 20 > x then 12 , 20, 22, 32, 42, 50 will work here
42+x > 20 all of the possibles work here
20 + x > 42 32, 42, 50, 62 and 70 work here
so 32 and 42 are in all of the lists ....that is your answer