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amid [387]
2 years ago
13

Suppose y varies directly with x.If x is 30 when y is 10, what is x when y is 9?

Mathematics
1 answer:
PtichkaEL [24]2 years ago
5 0

Step-by-step explanation:

x×k = y

30×k = 10

k = 10/30 = 1/3

x×1/3 = 9

x = 27

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Look below <br> plzzzzz n thanks
NNADVOKAT [17]

Answer:

c.

Step-by-step explanation:

i actually dont know i just guessed

5 0
3 years ago
B Christian installed an electric pump to pump water from a borehole into a 30 000 litre cement dam. If the water is pumped at a
skelet666 [1.2K]

Given the amount of water needed to fill the cement dam and the water pump rate, the time needed to fill the dam is 400 minutes or 6hours 40minutes.

Option B)6h 40min is the correct answer.

<h3>How long does it take to fill the dam?</h3>

Given that;

  • Amount of water needed to fill the dam A = 30000 litres
  • Pump rate r = 75 litres per minute
  • Time needed to fill the dam T = ?

To determine how long it take to fill the dam, we say;

Time need = Amount of water needed ÷ Pump rate

T = A ÷ r

T = 30000 litres ÷ 75 litres/minute

T = 400 minutes

Note that; 60min = 1hrs

Hence,

T = 6hours 40minutes

Given the amount of water needed to fill the cement dam and the water pump rate, the time needed to fill the dam is 400 minutes or 6hours 40minutes.

Option B)6h 40min is the correct answer.

Learn more word problems here: brainly.com/question/2610134

#SPJ1

8 0
2 years ago
The coordinates of polygon ABCD are A(-4,-1), B(-2,3), C(2,2), and D(4,-3). Use these coordinates to complete the sentences belo
oee [108]

Answer:

The perimeter of polygon ABCD, to the nearest thousandth units is

22.227 units

The perimeter of polygon ABCD', to the nearest thousandth, would be 20.980 units

The area of polygon ABCD' is 19.5 units²

Step-by-step explanation:

The coordinates forming the polygon are

A (-4,-1), B(-2,3), C(2,2), and D(4,-3)

The perimeter then is given by the sum of the length of the sides as follows;

Length of line between two X and Y points distance, xi and yj apart is

length XY =  \sqrt{x^2+y^2}

Therefore, the length between points AB is

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

= \sqrt{(-4 +2)^2+(-4)^2} = \sqrt{-2^2+-4^2}  = \sqrt{20}  = 4.472 units

Similarly, length BC is given by

Length BC =  \sqrt{(-4)^2+1^2} =  \sqrt{17} = 4.123 units

Length CD = \sqrt{(-2)^2+5^2} =  \sqrt{29} = 5.385 units

Length DA = \sqrt{(8)^2+(-2)^2} =  \sqrt{68} = 8.246 units

The perimeter is equal to;

length AB + Length BC + Length CD + Length DA

= 4.472 + 4.123 + 5.385 + 8.246 = 22.227 units

If the point D is moved up 2 units and left 1 unit we have

D' = x-1, y+2 where x and y are the coordinates of point D

D(4, -3) → D'((4-1), (-3+2)) = D'(3, -1)

The length D'A =  \sqrt{(7)^2+(0)^2} =  \sqrt{49} =7 units

The perimeter of polygon ABCD'

length AB + Length BC + Length CD + Length D'A

= 4.472 + 4.123 + 5.385 + 7 = 20.980 units.

The area is given by the determinant of the 3 by 3 matrix using Cramer's Rule as follows

 S_{\bigtriangleup} = (\frac{1}{2})|x_1y_2+x_2y_3+x_3y_1-x_1y_3-x_2y_1-x_3y_2|

= (\frac{1}{2})|x_1(y_2-y_3)+x_2(y_3-y_1) +x_3(y_1-y_2)|

Triangle ABC we have

A(-4,-1)

B(-2,3)

C(2,2)

S_{{\bigtriangleup}ABC} = (\frac{1}{2})|x_1(y_2-y_3)+x_2(y_3-y_1) +x_3(y_1-y_2)|

=(\frac{1}{2})|(-4)(3-2)+(-2)(2-(-1)) +2((-1)-3)|

= =(\frac{1}{2})|-4-6 -8|= 9 units^2

Triangle ACD'

A(-4,-1)

C(2,2)

D'(3, -1)

S_{{\bigtriangleup}ACD'} = (\frac{1}{2})|x_1(y_2-y_3)+x_2(y_3-y_1) +x_3(y_1-y_2)|

=(\frac{1}{2})|(-4)(2+1)+(2)(-1+1) +3((-1)-2)| = \frac{21}{2} = 10.5 units²

Area of polygon =   S_{{\bigtriangleup}ABCD'} = S_{{\bigtriangleup}ABC} + S_{{\bigtriangleup}ACD'} = (9 + 10.5) units²

Area of polygon ABCD' = 19.5 units².

7 0
3 years ago
A man drove his car at 80km per hr for 1 and a quarter hrs .He rested for 45mins and then covered 240km, at the same time. Calcu
prisoha [69]

Answer:

Probably 128 km/h, but maybe 98.5 km/h. See below.

Step-by-step explanation:

What does "at the same time" mean?

If it means that he covered the 240 km in the same time as he convered the 80 km, then this is how you solve it:

80 km in 1.25 hour

240 km in 1.25 hour

Total distance: 80 km + 240 km = 320 km

Total time: 1.25 hour + 1.25 hour = 2.5 hour

average speed = (total distance)/(total time) = 320 km / 2.5 hour = 128 km/h

If it means he covered the 240 km in the same time he covered the 80 km plus the rest, then this is how you solve it:

80 km in 1.25 hour

240 km in 1.25 hour + 45 min = 240 km in 1.25 houir + 0.75 hour = 240 km in 2 hour

Total distance: 80 km + 240 km = 320 km

Total time: 1.25 hour + 2 hour = 3.25 hour

average speed = (total distance)/(total time) = 320 km / 3.25 hour = 98.5 km/h

3 0
2 years ago
The sum of 3 consecutive even integers is 576. Find the integers
alisha [4.7K]
You can write the equation
x+1+x+3+x+5=576
Combine like terms
3x+9=576
Subtract 9 from both sides
3x+9-9=576-9
3x=567
Divide both sides by 3
3x/3=567/3
x=189
 The first integer is 190, the second is 192 and the third is 194 (enter it into the original equation to get those answers)
4 0
3 years ago
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