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3 years ago

Lily cleans 3 houses in 7.5 hours. If she works 8-hour days for 7 days (with no breaks), how many houses could she clean?

Mathematics

1 answer:

Yakvenalex [24]3 years ago

7 0

Answer:

About 21 houses in 7 days

Step-by-step explanation:

You might be interested in

Covert 1/16in to mm (rounded to the nearest tenth)

mel-nik [20]

1/25.4 = (1/16)/x....1 in to 25.4mm = 1/16 in to x mm
cross multiply
x = 25.4 * 1/16
x = 25.4/16
x = 1.59 mm

3 0

3 years ago

When y=7.5 x=2 what is the value of y when x is 2 1/4

swat32

<h2>Answer:</h2>

The value of y is 8.4375

<h2>Step-by-step explanation:</h2><h3>Known :</h3>

y = 7.5
x = 2

<h3>Asked :</h3>

The value of y when x is 2.25

<h3>Solution :</h3>

2/7.5 = 2.25/y

Do a cross multiplication,

2/7.5 = 2.25/y

=> 20/75 = 2.25/y

=> 75 . 2.25 = 20y

=> 168.75 = 20y

Reverse the equation,

168.75 = 20y

=> 20y = 168.75

Find the value of y,

20y = 168.75

=> y = 8.4375

<h3>Conclusion :</h3>

y = 8.4375

7 0

3 years ago

A quadrilateral has vertices at $(0,1)$, $(3,4)$, $(4,3)$ and $(3,0)$. Its perimeter can be expressed in the form $a\sqrt2+b\sqr

seraphim [82]

Answer:

a + b = 12

Step-by-step explanation:

Given

Quadrilateral;

Vertices of (0,1), (3,4) (4,3) and (3,0)

$Perimeter = a\sqrt{2} + b\sqrt{10}$

Required

$a + b$

Let the vertices be represented with A,B,C,D such as

A = (0,1); B = (3,4); C = (4,3) and D = (3,0)

To calculate the actual perimeter, we need to first calculate the distance between the points;

Such that:

AB represents distance between point A and B

BC represents distance between point B and C

CD represents distance between point C and D

DA represents distance between point D and A

Calculating AB

Here, we consider A = (0,1); B = (3,4);

Distance is calculated as;

$Distance = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}$

$(x_1,y_1) = A(0,1)$

$(x_2,y_2) = B(3,4)$

Substitute these values in the formula above

$Distance = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}$

$AB = \sqrt{(0 - 3)^2 + (1 - 4)^2}$

$AB = \sqrt{( - 3)^2 + (-3)^2}$

$AB = \sqrt{9+ 9}$

$AB = \sqrt{18}$

$AB = \sqrt{9*2}$

$AB = \sqrt{9}*\sqrt{2}$

$AB = 3\sqrt{2}$

Calculating BC

Here, we consider B = (3,4); C = (4,3)

Here,

$(x_1,y_1) = B (3,4)$

$(x_2,y_2) = C(4,3)$

Substitute these values in the formula above

$Distance = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}$

$BC = \sqrt{(3 - 4)^2 + (4 - 3)^2}$

$BC = \sqrt{(-1)^2 + (1)^2}$

$BC = \sqrt{1 + 1}$

$BC = \sqrt{2}$

Calculating CD

Here, we consider C = (4,3); D = (3,0)

Here,

$(x_1,y_1) = C(4,3)$

$(x_2,y_2) = D (3,0)$

Substitute these values in the formula above

$Distance = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}$

$CD = \sqrt{(4 - 3)^2 + (3 - 0)^2}$

$CD = \sqrt{(1)^2 + (3)^2}$

$CD = \sqrt{1 + 9}$

$CD = \sqrt{10}$

Lastly;

Calculating DA

Here, we consider C = (4,3); D = (3,0)

Here,

$(x_1,y_1) = D (3,0)$

$(x_2,y_2) = A (0,1)$

Substitute these values in the formula above

$Distance = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}$

$DA = \sqrt{(3 - 0)^2 + (0 - 1)^2}$

$DA = \sqrt{(3)^2 + (- 1)^2}$

$DA = \sqrt{9 + 1}$

$DA = \sqrt{10}$

The addition of the values of distances AB, BC, CD and DA gives the perimeter of the quadrilateral

$Perimeter = 3\sqrt{2} + \sqrt{2} + \sqrt{10} + \sqrt{10}$

$Perimeter = 4\sqrt{2} + 2\sqrt{10}$

Recall that

$Perimeter = a\sqrt{2} + b\sqrt{10}$

This implies that

$a\sqrt{2} + b\sqrt{10} = 4\sqrt{2} + 2\sqrt{10}$

By comparison

$a\sqrt{2} = 4\sqrt{2}$

Divide both sides by $\sqrt{2}$

$a = 4$

By comparison

$b\sqrt{10} = 2\sqrt{10}$

Divide both sides by $\sqrt{10}$

$b = 2$

Hence,

a + b = 2 + 10

a + b = 12

3 0

3 years ago

What are the x and y values....?<br><br> -1x + 2y = 18 <br><br> Haylp me pls!

Nesterboy [21]

Use the zeroes to figure this out... x=-18, y=9

7 0

4 years ago

Cory's average score after 8 tests is 91%. If he gets a 78% on his 9th test what will his new average be?

Luda [366]

You should be able to multiply 91 by 8 to get the sum of the first 8 tests, then add the score on the 9th test. Then to get the average of the sum of the 9 tests you need to divide it by 9.
((91*8)+78)/9=89.555555555555.... So, 90%

3 0

4 years ago