What I would do for the first one:
"If 32 and 43 make 35 then 76 and 15 make ____"
is look for a linear relation, just because that is easiest. That is, look for numbers, a and b, such that 32a+ 43b= 35 and a+ b= 1. multiply a+ b= 1 by 32 to get 32a+ 32b= 32 and subtract that from 32a+ 43b= 35. (32- 32)a+ (43- 32)b= 11b= 35- 32= 3. Then b= 3/11. Putting that into a+ b= 1, a+ 3/11= 1 so a- 1- 3/11= 8/11.
Now, 75a+ 15b= 600/11+ 45/11= 645/11. My answer would be that "76 and 15 make 645/11".
Of course, I have no way of knowing if that was what was intended but it meets all the requirements of the problem!
For the next, I would note that 3+ 6+ 11= 20 and 13+ 10+ 7= 30. Aha! I say. I should find "?" so that 15+ ?+ 3= 18+ ?= 40! That is, ?= 40- 18= 22.
Again, I have no way of knowing if that was intended but it meets all the requirements of the problem.