The Minimum sample size table is attached below
Answer:

Step-by-step explanation:
From the question we are told that:
Confidence Interval 
Variance 
Generally going through the table the
Minimum sample size is

Answer:
10650
Step-by-step explanation:
Answer:
x=2, y=16
Step-by-step explanation:
x+y=18
y=8x
x+8x=18
x=2
y=16
X=117 degrees
Y = 63 degrees
Z = 117 degrees
2x - y = 7
y = 2x - 7 this line has slope = 2
Perpendicular lines, slope is opposite and reciprocal so slope = -1/2
Answer
A . -1/2