After buying some marbles for $83.40, thomas has $17.19 left. how much money did thomas have to bring in with

What is the smallest integer n such that n\sqrt{2} is greater than 20

Can any one me with the answers to these questions asap?

Im gonna fail 7th grade selective breeding 1. creates offspring which are genetically identical to the parent 2. is the process of breeding only organisms with desirable traits 3. involves the removal of the nucleus of a cell 4. combines traits from organisms of different species