Answer:
C, D, and E
Step-by-step explanation:
When trying to solve for the cost of each item you will find a rainbow fish is $8.50 and a tetra is $2.50. If you use that information to solve the other answer choices C, D, and E would be correct
The first one
2,6,8,3,7,9,4,9,8,7,3,2,8,11,3
Answer:

Step-by-step explanation:
The pool are is divided into 4 separated shapes: 2 circular sections and 2 isosceles triangles. Basically, to calculate the whole area, we need to find the area of each section. Due to its symmetry, both triangles are equal, and both circular sections are also the same, so it would be enough to calculate 1 circular section and 1 triangle, then multiply it by 2.
<h3>Area of each triangle:</h3>
From the figure, we know that <em>b = 20ft </em>and <em>h = 25ft. </em>So, the area would be:

<h3>Area of each circular section:</h3>
From the figure, we know that
and the radius is
. So, the are would be calculated with this formula:

Replacing all values:

Remember that 
Therefore, 
Now, the total are of the figure is:

Therefore the area of the symmetrical pool is 
Answer:
0.2008 = 20.08% probability that among 150 calls received by the switchboard, there are at least two wrong numbers.
Step-by-step explanation:
In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

In which
x is the number of sucesses
e = 2.71828 is the Euler number
is the mean in the given interval.
The probability that a call received by a certain switchboard will be a wrong number is 0.02.
150 calls. So:

Use the Poisson distribution to approximate the probability that among 150 calls received by the switchboard, there are at least two wrong numbers.
Either there are less than two calls from wrong numbers, or there are at least two calls from wrong numbers. The sum of the probabilities of these events is 1. So

We want to find
. So

In which





Then

0.2008 = 20.08% probability that among 150 calls received by the switchboard, there are at least two wrong numbers.