Given that,
The given expression is : 
To find,
The value of the above expression when x = 2 and y = 4
Solution,
We have,

Put x = 2 and y = 4 in the above expression.

So, the value of the above expression is 18.
the answer that I came up with is (c)
8 units
Circumference = pi * 2 * radius
50.24 = 3.14 * 2 * radius
50.24 = 6.28 * radius
8 = radius
Answer:
d. (0.737, 0.823)
The 90% confidence interval is = (0.737, 0.823)
Step-by-step explanation:
Confidence interval can be defined as a range of values so defined that there is a specified probability that the value of a parameter lies within it.
The confidence interval of a statistical data can be written as.
p+/-z√(p(1-p)/n)
Given that;
Proportion p = 195/250 = 0.78
Number of samples n = 250
Confidence interval = 90%
z value(at 90% confidence) = 1.645
Substituting the values we have;
0.78 +/- 1.645√(0.78(1-0.78)/250)
0.78 +/- 1.645√(0.0006864)
0.78 +/- 1.645(0.026199236630)
0.78 +/- 0.043097744256
0.78 +/- 0.043
(0.737, 0.823)
The 90% confidence interval is = (0.737, 0.823)