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KATRIN_1 [288]
3 years ago
8

A large concrete mixing machine can mix a certain amount of concede in 12 hours, while a smallet one can mix

Mathematics
1 answer:
Andrews [41]3 years ago
5 0

Answer:

[(1/12)(5/5) + (1/20)(3/3)](x hours) = 1

(5/60 + 3/60)x = 1

(8/60)x = 1 we can reduce 8/60 by dividing out a 4

(2/15)x = 1 x both sides by 15/2

x = 15/2

x = 7 1/2 or 7.5 hours

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PLEASE HELPPPPP!!!
Vladimir [108]

Step-by-step explanation:

Slope-intercept form: y = mx + c

We have m = 1/4. Since it passes through the

point (-4, 2), => When x = -4, y = 2.

=> (2) = (1/4)(-4) + c, 2 = c - 1, c = 3.

Hence the equation is y = x/4 + 3.

8 0
3 years ago
Read 2 more answers
An urn contains three white balls and two red balls. The balls are drawn from the urn, oneat a time without replacement, until a
Tpy6a [65]

Answer:

p ( X = 1 ) = 0.6 , p ( X = 2 ) = 0.3 , p ( X = 3 ) = 0.1

Verified

E ( X ) = 1.5

Step-by-step explanation:

Solution:-

- An urn contains the following colored balls:

                       Color                  Number of balls

                       White                            3

                       Red                               2

- A ball is drawn from urn without replacement until a white ball is drawn for the first time.

- We will construct cases to determine the distribution of the random-variable X: The number of trials it takes to get the first white ball.

- We have three following case:

1) White ball is drawn on the first attempt ( X =  1 ). The probability of drawing a white ball in the first trial would be:

              p ( X = 1 ) = ( Number of white balls ) / ( Total number of ball )

              p ( X = 1 ) = ( 3 ) / ( 5 )

2) A red ball is drawn on the first draw and a white ball is drawn on the second trial ( X = 2 ). The probability of drawing a red ball first would be:

      p ( Red on first trial ) = ( Number of red balls ) / ( Total number of balls )

      p ( Red on first trial ) = ( 2 ) / ( 5 )

- Then draw a white ball from a total of 4 balls left in the urn ( remember without replacement ).

   p ( White on second trial ) = ( Number of white balls ) / ( number of balls left )

   p ( White on second trial ) = ( 3 ) / ( 4 )

- Then to draw red on first trial and white ball on second trial we can express:

                p ( X = 2 ) =  p ( Red on first trial ) *  p ( White on second trial )

                p ( X = 2 ) =  ( 2 / 5 ) * ( 3 / 4 )

                p ( X = 2 ) =  ( 3 / 10 )  

3) A red ball is drawn on the first draw and second draw and then a white ball is drawn on the third trial ( X = 3 ). The probability of drawing a red ball first would be ( 2 / 5 ). Then we are left with 4 balls in the urn, we again draw a red ball:

   p ( Red on second trial ) = ( Number of red balls ) / ( number of balls left )

   p ( Red on second trial ) = ( 1 ) / ( 4 )    

 

- Then draw a white ball from a total of 3 balls left in the urn ( remember without replacement ).                  

   p ( White on 3rd trial ) = ( Number of white balls ) / ( number of balls left )

   p ( White on 3rd trial ) = ( 3 ) / ( 3 ) = 1

- Then to draw red on first two trials and white ball on third trial we can express:

                p ( X = 3 ) =  p ( Red on 1st trial )*p ( Red on 2nd trial )*p ( White on 3rd trial )

                p ( X = 3 ) =  ( 2 / 5 ) * ( 1 / 4 ) * 1

                p ( X = 3 ) =  ( 1 / 10 )  

- The probability distribution of X is as follows:

    X          1                  2                      3

p ( X )      0.6               0.3                  0.1

- To verify the above the distribution. We will sum all the probabilities for all outcomes ( X = 1 , 2 , 3 ) must be equal to 1.

          ∑ p ( Xi ) = 0.6 + 0.3 + 0.1

                         = 1 ( proven it is indeed a pmf )

- The expected value E ( X ) of the distribution i.e the expected number of trials until we draw a white ball for the first time:

               E ( X ) = ∑ [ p ( Xi ) * Xi  ]

               E ( X ) = ( 1 ) * ( 0.6 ) + ( 2 ) * ( 0.3 ) + ( 3 ) * ( 0.1 )

               E ( X ) = 0.6 + 0.6 + 0.3

               E ( X ) = 1.5 trials until first white ball is drawn.

8 0
3 years ago
Please respond ASAP (Free response be specific and explain ! thanks )
Neporo4naja [7]

Answer:

No it's not, because a square has all the sides equal, but this hasn't, therefore it's not a square

4 0
3 years ago
A baker makes a total of 5 loaves of bread in 2.5 hours. At that rate, how many loaves of bread could the baker make in 7 hours?
damaskus [11]

Answer:

14 =x

Step-by-step explanation:

We can use ratios to solve

5 loaves          x loaves

-------------  = ---------------

2.5 hours          7 hours

5 * 7 = 2.5 x

Divide by 2.5

35/2.5 = 2.5x/2.5

14 =x

4 0
3 years ago
Read 2 more answers
A health food company sells packs of assorted nuts. The company incurs a monthly fixed cost of $1,400 for ingredients and raw ma
torisob [31]
<span>The expression that represents the total cost (y) of manufacturing
x bags of nuts in a month is

</span>                                   <span>y = x + 1,400 </span>
6 0
3 years ago
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