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3 years ago

How do you solve this problem 5(x-3)+7=5x-8

1 answer:

4 0

5(x-3)+7=5x-8
5*x=5x 5*3=15
5x-15+7=5x-8
15+7=22
5x-22=5x-8
5x+5x=10x
10x-22=8
22+8=30
10x=30
---------- (Divide by 10 to get x alone)
10
x=3

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An instructor who taught two sections of engineering statistics last term, the first with 25 students and the second with 35, de

Amiraneli [1.4K]

Answer:

a) P=0.1721

b) P=0.3528

c) P=0.3981

Step-by-step explanation:

This sampling can be modeled by a binominal distribution where p is the probability of a project to belong to the first section and q the probability of belonging to the second section.

a) In this case we have a sample size of n=15.

The value of p is p=25/(25+35)=0.4167 and q=1-0.4167=0.5833.

The probability of having exactly 10 projects for the second section is equal to having exactly 5 projects of the first section.

This probability can be calculated as:

$P=\frac{n!}{(n-k)!k!}p^kq^{n-k}= \frac{15!}{(10)!5!}\cdot 0.4167^5\cdot0.5833^{10}=0.1721$

b) To have at least 10 projects from the 2nd section, means we have at most 5 projects for the first section. In this case, we have to calculate the probability for k=0 (every project belongs to the 2nd section), k=1, k=2, k=3, k=4 and k=5.

We apply the same formula but as a sum:

$P(k\leq5)=\sum_{k=0}^{5}\frac{n!}{(n-k)!k!}p^kq^{n-k}$

Then we have:

$P(k=0)=0.0003\\P(k=1)=0.0033\\P(k=2)=0.0165\\P(k=3)=0.0511\\P(k=4)=0.1095\\P(k=5)=0.1721\\\\P(k\leq5)=0.0003+0.0033+0.0165+0.0511+0.1095+0.1721=0.3528$

c) In this case, we have the sum of the probability that k is equal or less than 5, and the probability tha k is 10 or more (10 or more projects belonging to the 1st section).

The first (k less or equal to 5) is already calculated.

We have to calculate for k equal to 10 or more.

$P(k\geq10)=\sum_{k=10}^{15}\frac{n!}{(n-k)!k!}p^kq^{n-k}$

Then we have

$P(k=10)=0.0320\\P(k=11)=0.0104\\P(k=12)=0.0025\\P(k=13)=0.0004\\P(k=14)=0.0000\\P(k=15)=0.0000\\\\P(k\geq10)=0.032+0.0104+0.0025+0.0004+0+0=0.0453$

The sum of the probabilities is

$P(k\leq5)+P(k\geq10)=0.3528+0.0453=0.3981$

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3 years ago

A clock that loses seconds each hour has not been reset for 48 hours. What time does the clock show if the correct time is 8:49?

lys-0071 [83]

Answer:

how many seconds per hour?

Step-by-step explanation:

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3 years ago

Read 2 more answers

A 24-centimeter by 119-centimeter piece of cardboard is used to make an open-top box by removing a square from each corner of th

satela [25.4K]

Answer:

The size square removed from each corner = 32.15 cm²

Step-by-step explanation:

The volume of the box = Length * Breadth * Height

Let r be the size removed from each corner

Note that at maximum volume, $\frac{dV}{dr} = 0$

The original length of the cardboard is 119 cm, if you remove a size of r (This typically will be the height of the box) from the corner, since there are two corners corresponding to the length of the box, the length of the box will be:

Length, L = 119 - 2r

Similarly for the breadth, B = 24 - 2r

And the height as stated earlier, H = r

Volume, V = L*B*H

V = (119-2r)(24-2r)r

V = r(2856 - 238r - 48r + 4r²)

V = 4r³ - 286r² + 2856r

At maximum volume dV/dr = 0

dV/dr = 12r² - 572r + 2856

12r² - 572r + 2856 = 0

By solving the quadratic equation above for the value of r:

r = 5.67 or 42

r cannot be 42 because the size removed from the corner of the cardboard cannot be more than the width of the cardboard.

Note that the area of a square is r²

Therefore, the size square removed from each corner = 5.67² = 32.15 cm²

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3 years ago

Brandon bought three pounds of bananas for $1.35. How much would ten pounds of bananas cost at the same price per pound?

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Take 1.35/3 and take that number x10 to get $4.50

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3 years ago

Find the pattern. What numbers come next?

insens350 [35]

53,61,69

it’s adding 8 every time.

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3 years ago