3. An electric bill is an essential expense for young people who get their first apartment. The following is a list of Jordan's monthly electric bills for the past
10 months.
$115,
$150, $144, $126, $90, $90, $95, $110, $120, $88
Round your answers to the nearest cent.
a. What is the mean monthly electric bill?
b. What is the range?
c. What is the variance?
d. What is the standard deviation?

Mean = $123.8

Range= $72

Variance= $607.344

Standard deviation=$ 24.64

Step by step explanation:

The list of the data of electricity bill on ascending order

$88,$90,$90,$95,$110,$115,$120,$126,$144,$150

Mean = (summation of($88,$90,$90,$95,$110,$115,$120,$126,$144,$150))/10

Mean = 1238/10

Mean = $123.8

Range= highest value- Lowest VA

Range= 150-88

Range= $72

Variance=( (88-123.8)²+(90-123.8)²+(90-123.8)²+(95-123.8)²+(110-123.8)²+(115-123.8)²+(120-123.8)²+(126-123.8)²+(144-123.8)²+(150-123.8)²)/10

Variance= (1281.64+1142.44+1142.44+829.44+190.44+77.44+14.44+4.84+295.84+408.04+686.44)/10

Variance= 6073.44/10

Variance=$ 607.344

Standard deviation= √variance

Standard deviation= √ 607.344

Standard deviation=$ 24.64

(b) 240

step-by-step explanation:

first, we use the pythagorean formula using the given side lengths to find x. then we use x to find the side lengths. then we add the side lengths to find the perimeter.

pythagorean theorem formula:

a^2 + b^2 = c^2

(x - 20)^2 + (x - 40)^2 = x^2

x^2 - 40x + 400 + x^2 - 80x + 1600 = x^2

x^2 -120x + 2000 = 0

(x - 100)(x - 20) = 0

x - 100 = 0 or x - 20 = 0

x = 100 or x = 20

we see that the solution x = 20 must be discarded because it will give a negative side length and a side length of 0. the only valid solution is x = 100.

perimeter = sum of the lengths of the sides

perimeter = x + x - 20 + x - 40

perimeter = 3x - 60

replace x with 100.

perimeter = 3(100) - 60

perimeter = 300 - 60

perimeter = 240