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hodyreva [135]
3 years ago
9

It takes Jimmy 11 minutes to sweep a porch.

Mathematics
2 answers:
Katena32 [7]3 years ago
7 0

Answer:

5.96 min

Step-by-step explanation:

Jimmy's rate, J = 11 min for whole porch

Amy's rate, A = 13 min for whole porch

to find the combined rate, C,

the reciprocal of the combined rate equals the sum of the reciprocals of each individual rate. i.e

1/C = 1/J + 1/A

substituting the above values

1/C = 1/11 + 1/13  (convert right side to same denominator)

1/C = 13 / (11 x 13)  + 11 / (11 x 13)

1/C = 13 /143 + 11 /143

1/C = (13 + 11) /143

1/C = 24 /143   (taking reciprocal of both sides)

C = 143 / 24 = 5.96 min

lara31 [8.8K]3 years ago
4 0
Like 6 minutes or somthin
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The volume of a right cylinder is V = πr2h. If we have an oblique cylinder, like in the figure, what is the volume of a cross-se
olchik [2.2K]
Since you did not attach any picture we cannot say for sure what is the correct answer, but we can discuss the options in order to find the most probable correct answer.

First of all, according to the Cavalieri's principle, an oblique cylinder has the same volume as a right cylinder with the same base surface area and same height.
A cross-section of an oblique cylinder will be a small right cylinder with the same base surface area and a height as small as possible.

I guess the oblique cylinder has height h and it is divided into many (probably 10) cross-sections.

Option A: <span>πr2h
This is exactly the volume of the right cylinder, therefore, unless you are given a cross-section of height h (which would be too easy), this won't be the correct answer.

Option B: </span><span>4πr2h
This is 4 times the right cylinder. Again, here the height of the cross-section should</span> be 4h, but it doesn't sound like a possible data (too easy again).

Option C: <span>1 10 πr2h
Here comes a n issue with the notation: I think the right number you meant to write is (1/10)</span>·πr2h and not 110·<span>πr2h.
If I am right, this means that your oblique cylinder of height h is divided into 10 cross-sections, and therefore the volume of each of these cross-sections will be a tenth of the volume of the oblique cylinder, which means </span>1/10·<span>πr2h.

Option D: </span><span>1 2 πr2h
Here, we have the same notation issue as before. I think you meant (1/2)</span>·<span>πr2h.
Here, your oblique cylinder height h should be divided into only 2 cross-sections. Now, we said the cross-section's height should be the smallest as possible, so an oblique cylinder divided only into two pieces doesn't sound good.

Therefore, the most probable correct answer will be C) </span>(1/10)·<span>πr2h</span>
8 0
3 years ago
Read 2 more answers
Evaluate the expression when x = 9.<br>x + 5(x + 2)​
jasenka [17]

Answer:

64

Step-by-step explanation:

x + 5(x + 2)​

Distribute

x + 5x+10

Combine like terms

6x+10

Let x = 9

6(9) +10

54+10

64

8 0
3 years ago
Read 2 more answers
The number of E.coli bacteria cells in a pond of stagnant water can be represented by the function below, where A represents the
liq [111]

Answer:

  • <u>Option B. 59%</u>

Explanation:

The function that represents the number of E.coli bacteria cells per 100 mL of water as the time t years elapses is:

  • A(t)=136(1.123)^{4t}

The base, 1.123, represents the multiplicative constant rate of change of the function, so you just must substitute 1 for t in the power part of the function:

  • rate=(1.123)^{4t}=(1.123)^4=1.590

Then, the multiplicative rate of change is 1.590, which means that every year the number of E.coli bacteria cells per 100 mL of water increases by a factor of 1.590, and that is 1.59 - 1 = 0.590 or 59% increase.

8 0
3 years ago
$200 at 15.5% for 2 years
Inessa05 [86]
15.5 I believe but don’t hold me to it!
8 0
2 years ago
What is the equation of a line with a slope of 4 and a y-intercept of 2?
Trava [24]

Answer:

y=4x+2 or f(x)=4x+2

Step-by-step explanation:

This is because the equation format for a line is y=mx+b, the slope is m and the y-intercept is b. So all you have to do is fill it out to get y=4x+2. Or the other way I listed the equation is right too. Hope this helps!

6 0
2 years ago
Read 2 more answers
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