5 Questions, 12 points per question, and for the last I'll need a step by step explanation.

Adrawer contains 12 identical white socks, 18 identical black socks and 14 identical brown socks. what is the least number of socks you must choose, without looking, to be certain that you have chosen two socks of the same colour?

Acircle has a circumference of 28.36 units what is the diameter of the circle

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?