#1) 5/20
#2) 7/300
#3) 3/50
#4) 5/20
Explanation
For #1:
There are 15 even numbers out of 30. Since it is replaced before drawing the second ball, there will be 15 odd numbers out of 30. This gives us
15/30(15/30) = 225/900 = 5/20.
For #2:
There is 1 7 out of 30; then there are 14 numbers greater than 16 out of 30:
1/30(14/30) = 14/900 = 7/300
For #3:
There are 6 multiples of 5 out of 30; then there are 9 prime numbers out of 30:
6/30(9/30) = 54/900 = 3/50
For #4:
There are 15 even numbers out of 30; then there are still 15 even numbers out of 30:
15/30(15/30) = 225/900 = 5/20
Think of the point, P, where the lines intersect as the center of a circle. The four angles with vertex P add up to 360 degrees. The given angle and its paired vertical angle are both 30 degrees. So, the other two angles are also vertical angles with sum 300 degrees (so each of them is a 150 degree angle).
C (the one that looks like a circle)
This one has a pattern of (x+2)2
Just find an equation that fits the relationship between x and y
