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Skyscraper Windows

Musya8 [376]

Answer:

A.) $2,166

B.) $10,545

C.) (n/2)(3.5 + 0.5n) × 38

Step-by-step explanation:

Floor - - - - - - - - - - 1 - - - - - - - 2 - - - - - - - 3

Cost / window - - $2.00 - - - $2.50 - - - $3.00

Cost of washing first floor = $2 × 38

Cost of second floor is: (2 + 0.5) × 38

Cost of third floor is: (2 + 2 × 0.5) × 38

Cost of n floor : (2 + (n - 1) × 0.5) × 38

Therefore,

Total cost :

(2 + (2 + 0.5) + (2 + 2*0.5) + ... + (2 + (n - 1)*0.5)) × 38

Using Arithmetic progression for the sequence :

2, (2 + 0.5), (2 + 2*0.5),..., (2 + (n - 1)*0.5)

first term 'a' = 2; common difference 'd' = 0.5

Sum of the first n terms of arithmetic sequence terms is:

S = (n/2)(2a + (n - 1)d) ; Where a = 2 and d = 0.5

S = (n/2)(2*2 + (n - 1)*0.5)

S = (n/2)(4 + 0.5n - 0.5)

S = (n/2)(3.5 + 0.5n)

To wash all windows with n stories :

S × 38 windows

A.) To wash all windows : stories = 12

n = 12

(12/2)(3.5 + 0.5(12)) × 38

6(3.5 + 6) × 38 = $2,166

B.) if building is 30 stories tall:

n = 30

(30/2)(3.5 + 0.5(30)) × 38

15(3.5 + 15) × 38 = $10,545

C.) If building is n stories tall :

(n/2)(3.5 + 0.5n) × 38

4 0

2 years ago

El valor numérico de la expresión 〖P(y)=y〗^2-7y+10 para y=2 es: a. P(2)=9 b. P(2)=0 c. P(2)=-2 d. P(2)=-5

nika2105 [10]

Answer:

Opción b, P(2) = 0

Step-by-step explanation:

Tenemos la expresión:

P(y) = y^2 - 7*y + 10

Para encontrar el valor P(2), simplemente debemos remplazar todas las "y" en la expresión de arriba por el valor 2, asi obtenemos:

P(2) = 2^2 - 7*2 + 10 = 4 - 14 + 10 = (4 - 14) + 10 = -10 + 10 = 0

P(2) = 0

La opción correcta es b.

8 0

2 years ago

Ashley wants to pour 15.82 grams of salt into a container. So far, she has poured 13.87 grams. How much more salt should Ashley

erik [133]

Answer:

1.95

Step-by-step explanation:

Basically, you subtract: 5.82 - 13.87 = 1.95

Then, see: 15.82 - 1.950 = 13.87

Then you have your answer :D

Ashley has to pour 1.95 more grams of salt.

Brainliest, please??? :>

3 0

1 year ago

Read 2 more answers

Derek spends $8.50 a day on school breakfasts and lunches. How much does he spend on food in a school week? (Hint: there are 5 d

Anit [1.1K]

Answer:

$42.50

Step-by-step explanation:

$8.50 x 5 days = $42.50

5 0

2 years ago

Read 2 more answers

A population of monkeys' tail lengths is normally distributed with a mean of 25 cm with a standard deviation of 8 cm. I am prepa

Crank

Answer:

The probability that the mean of my sample will be between 24 and 25 cm

P(24 ≤X⁻≤25) = 0.4772

Step-by-step explanation:

Step(i):-

Given mean of the Population 'μ'= 25c.m

Given standard deviation of the Population 'σ' = 8c.m

Given sample size 'n' = 256

Let X₁ = 24

$Z_{1} = \frac{x_{1}-mean }{\frac{S.D}{\sqrt{n} } } = \frac{24-25}{\frac{8}{\sqrt{256} } } = -2$

Let X₂ = 25

$Z_{2} = \frac{x_{2}-mean }{\frac{S.D}{\sqrt{n} } } = \frac{25-25}{\frac{8}{\sqrt{256} } } = 0$

Step(ii):-

The probability that the mean of my sample will be between 24 and 25 cm

P(24 ≤X⁻≤25) = P(-2≤ Z ≤0)

= P( Z≤0) - P(Z≤-2)

= 0.5 + A(0) - (0.5- A(-2))

= A(0) + A(2) ( ∵A(-2) =A(2)

= 0.000+ 0.4772

= 0.4772

Final answer:-

The probability that the mean of my sample will be between 24 and 25 cm

P(24 ≤X⁻≤25) = 0.4772

4 0

2 years ago