Help please! im struggling with all of these

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

Choosing a booth location: your manager is sending two people to work at the conference. she wants a booth that will give your company good visibility for no more than 35% of the total budget ($3000). the conference coordinator just told you there are only five booths left. which booth will you choose? write the inequality that shows how much money you can spend on the booth simplify the inequality that shows how much money you can spend on the booth.

Agreeting card company can produce a box of cards for $7.50. if the initial investment by the company was $50,000, how many boxes of cards must be produced before the average cost per box falls to $10.50?