12, because 4 rows and 3 sections in each
4x3=12
Answer: 1:1
Step-by-step explanation:
Let r be the radius and h be the height of a cylinder.
Formula: Curved surface area of cylinder = 
Now, if radius of a cylinder is doubled and its height is halved, then new radius will be R= 2r and new height will be 
Now, new surface area = 
Ratio of curved surface areas : 
Hence, the ratios of their surface areas = 1:1 .
Answer:
The probability is 0.31
Step-by-step explanation:
In this question, we are tasked with calculating the probability that a random plumber called at Denver will charge an amount greater than $86 given the mean and the standard deviation.
Firstly, we calculate the standard score of $86 using the mean and the standard deviation.
Mathematically;
z-score = (x-mean)/SD
where x = 86, mean = 84 and SD = 4
z-score = (86-84)/4 = 2/4 = 0.5
Hence, we want to calculate P(z ≥ 0.5)
Using standard table
P( (z ≥ 0.5) = 1 - P(z ≤ 0.5) = 1 - ( 0.19146 + 0.5) = 0.30854
To the nearest hundredth = 0.31
