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3 years ago

Jackson can remove the shingles off of a house in 7 hours, while Martin can remove the shingles in 5 hours. How long will it

Mathematics

2 answers:

inessss [21]3 years ago

6 0

Answer:

It will take them 2 hours and 55 minutes to remove the shingles if they work together.

Step-by-step explanation:

The together rate is the sum of each separate rate.

In this problem:

Jackson's rate is 1/7

Martin's rate is 1/5.

The together rate is 1/x, which is what we want to find.

$\frac{1}{7} + \frac{1}{5} = \frac{1}{x}$

$\frac{5 + 7}{35} = \frac{1}{x}$

$\frac{12}{35} = \frac{1}{x}$

$12x = 35$

$x = \frac{35}{12}$

$x = 2.9167$

So 2 hours plus 0.9167 of an hour.

An hour has 60 minutes.

0.9167*60 = 55 minutes

So it will take them 2 hours and 55 minutes to remove the shingles if they work together.

kotegsom [21]3 years ago

4 0

Answer:

Step-by-step explanation:

WE can use the following formula:

$\frac{T}{X}+\frac{T}{Y}=1$

Where "T" is the time time working together,

"X" the time for person X working alone and

"Y" is the time for person Y working alone.

Based on the data given in the exercise, we can identify that:

$X=7\\Y=5$

substituting these values into the formula and solving for "T", we get that this is:

$\frac{T}{7}+\frac{T}{5}=1\\\\\frac{12T}{35}=1\\\\T=(1)(\frac{35}{12})\\\\T=2.9167\ hours$

Since 1 hour has 60 minutes:

$(0.9167h)(\frac{60min}{1h})\\=55min$

<h3> </h3><h3>Therefore, if they work together, it will take them 2 hours and 55 minutes to remove the shingles.</h3>

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The quality-control department of Starr Communications, the manufacturer of video-game cartridges, has determined from records t

notsponge [240]

Answer: (A) The probability that a cartridge purchased will have a video or audio defect is 1.9%

(B) The probability that a cartridge purchased will not have a video or audio defect is zero.

Step-by-step explanation: The data given shows that 1.2% (or 120) cartridges have video defects, 0.9% have audio defects (or 90) and 0.2% (or 20) have both audio and video defects.

The possible outcomes for all events (audio defects and video defects) is derived as 120 plus 90 which is equals 210 possibilities (or possible outcomes).

Therefore the probability of having an audio defect is calculated as follows;

P(Audio) = Number of required outcomes/Number of all possible outcomes

P(Audio) = 90/210

P(Audio) = 3/7

Also the probability of having a video defect is derived as follows;

P(Video) = Number of required outcomes/Number of all possible outcomes

P(Video) = 120/210

P(Video) = 4/7

However we should take note of the fact that 0.2% or 20 of the cartridges in the sample size has both audio and video defects. Hence the probability that a cartridge has both audio and video defects is calculated as;

P(Audio and Video) = Number of required outcomes/Number of all possible outcomes

P(Audio and Video) = 20/210

P(Audio and Video) = 2/21

To calculate the probability that a cartridge bought would have either an audio or a video defect would mean to add both probabilities together, but we MUST SUBTRACT the probability of having both an audio defect and video defect (that is P{Audio and Video}). The reason is that this is already included in both probabilities and we need to avoid double counting. Hence we have;

(A); P(Video OR Audio defect) = P(Audio) + P(Video) - P(Audio and Video)

P(Video OR Audio defect) = (3/7 + 4/7) - 2/21

P(Video OR Audio defect) = 1 - 2/21

P((Video OR Audio defect) = 19/21

Therefore the probability that a cartridge purchased will have a video or audio defect is 190, or better still 1.9%.

(B): From all possibilities shown, which is 210 possibilities of either events, we have determined that 120 will be the probability of having an audio defect and 90 will be the probability of having a video defect. Therefore the probability that a cartridge purchased will not fall into any of either possibilities is zero.

6 0

3 years ago

I’ll mark brainliest

enyata [817]

Answer:

$\text{A. }y=1.30x+1.50$

Step-by-step explanation:

The two ringtones will cost her a total of $0.75\cdot 2=1.50$ and is a fixed amount. The relationship between the cost and number of songs only is $y=1.30x$ and therefore the answer is $\boxed{\text{A. }y=1.30x+1.50}$ . You can also directly find the answer by finding the y-intercept (in this case $1.50$ ), as no other answer choices include the term $1.50$ , so A must be the correct answer.

6 0

2 years ago

What is the slope of the line that passes through the points (-8, -1)(−8,−1) and (-6, -2) ?(−6,−2)? Write your answer in simples

ziro4ka [17]

The slope of line passing through the given points is: -1/2

Step-by-step explanation:

Given points are:

(x1,y1) = (-8,-1)

(x2,y2) = (-6,-2)

Slope is defined as the steepness of a line.

It is denoted by m.

The formula for slope is:

$m = \frac{y_2-y_1}{x_2-x_1}$

Putting the values

$m = \frac{-2-(-1)}{-6-(-8)}\\= \frac{-2+1}{-6+8}\\=\frac{-1}{2}$

The slope of line passing through the given points is: -1/2

Keywords: Slope, steepness

Learn more about slope at:

#LearnwithBrainly

3 0

3 years ago

Keiko got a prepaid debit card and $15 on it. for her first purchase with the card she bought some bulk ribbon at a craft store.

kondaur [170]

Answer:

Step-by-step explanation:

$15 - $7.65 = $7.35

7.35/.21 = 35

5 0

1 year ago

Students in a class are asked to stand in ascending order according to their heights for the annual class photograph. Determine

horrorfan [7]

Answer:

The function in Python is as follows:

def heightChecker(heights):

expected = []

count = 0

for i in range(len(heights)):

expected.append(heights[i])

expected.sort()

for i in range(len(heights)):

if expected[i] != heights[i]:

count+=1

return count

Step-by-step explanation:

Required

Function to return the number of out of position students

<em>See comment for complete question</em>

This defines the function. It receives the heights as a parameter, from the main

def heightChecker(heights):

This initializes a list, (expected list)

expected = []

This initializes the count of out of position students

count = 0

This iterates through the original list

for i in range(len(heights)):

The list item is then appended to the expected list

expected.append(heights[i])

This sorts the expected list in ascending order

expected.sort()

This iterates through the original and the expected lists

for i in range(len(heights)):

If list elements at the same index are not the same, count is incremented by 1

<em> if expected[i] != heights[i]: </em>

<em> count+=1 </em>

This returns count

return count

4 0

2 years ago