Answer:
a) sample size is 40
Step-by-step explanation:
(a)
minutes
Margin of error, E is 75 seconds E=75/60= 1.25 minutes.
The level of significance 
for 95% level of significance
For 95% confidence interval 
from standard deviation table
Sample size required, n
Rounding off, n=40
Sample size =40
Keywords:
95% confidence, sample size, Wall Street Journal
Answer:
y = x - 2
Step-by-step explanation:
y + 4 = 1 (x + 2)
y + 4 = x + 2
y = x - 2
Answer:
X=3
Y=1
Step-by-step explanation:
In solving simultaneous equations, there are three methods, we have the elimination method, substitution method or graphical method. But for the purpose of this question, we would be using Elimination method.
5y-4x =-7 Equation 1
2y+4x=14 Equation 2
Since x has the same coefficient, it's easy to eliminate by adding up the two equations
5y+2y=7y
-4x+(+4x)=0
-7+(+14)=7
We have 7y=7
Divide both sides by 7,
y=7/7
y=1
Substituting for y in equation 2.
2(1)+4x=14
2+4x=14
4x=14-2
4x=12
x=12/4
x= 3
I got 6 for my answer, but I'm not 100% sure if I'm right.
6(2x-11)+15=21
12x-66+15=21
12x-51=21
+51 +51
12x=72
----- ----
12 12
x=6
