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3 years ago

James completed 18 math problems. This is 30% of the problems he has to do. How many math problems must he do?

2 answers:

5 0

If you know that the 18 completed problems are 30% then you divide 18 by .30 which I believe will give you 60 problems left

xenn [34]3 years ago

3 0

James has to do 60 Math problems

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on the same bus, 1/3 of the French speakers can also speak German. how many people can speak both German and French

Alenkinab [10]

It's easy if you just break it into pieces...

1/3 OF the 4/9 French OF people on the bus (27) also speak German.

Of= Multiply

1/3*4/9*27/1=4 speak French AND German

3 0

3 years ago

Victoria ran 3/4 a mile in 1/3 of an hour. If she continues at this rate, How far will she run in 1 hour

weqwewe [10]

Answer:

2 ¼ miles

Step-by-step explanation:

we can use a ratio

miles:hrs

¾:⅓

x3 x3

9/4:1

2¼:1

3 0

3 years ago

g A manufacturer is making cylindrical cans that hold 300 cm3. The dimensions of the can are not mandated, so to save manufactur

sdas [7]

Answer:

The dimensions that minimize the cost of materials for the cylinders have radii of about 3.628 cm and heights of about 7.256 cm.

Step-by-step explanation:

A cylindrical can holds 300 cubic centimeters, and we want to find the dimensions that minimize the cost for materials: that is, the dimensions that minimize the surface area.

Recall that the volume for a cylinder is given by:

$\displaystyle V = \pi r^2h$

Substitute:

$\displaystyle (300) = \pi r^2 h$

Solve for h:

$\displaystyle \frac{300}{\pi r^2} = h$

Recall that the surface area of a cylinder is given by:

$\displaystyle A = 2\pi r^2 + 2\pi rh$

We want to minimize this equation. To do so, we can find its critical points, since extrema (minima and maxima) occur at critical points.

First, substitute for h.

$\displaystyle \begin{aligned} A &= 2\pi r^2 + 2\pi r\left(\frac{300}{\pi r^2}\right) \\ \\ &=2\pi r^2 + \frac{600}{ r} \end{aligned}$

Find its derivative:

$\displaystyle A' = 4\pi r - \frac{600}{r^2}$

Solve for its zero(s):

$\displaystyle \begin{aligned} (0) &= 4\pi r - \frac{600}{r^2} \\ \\ 4\pi r - \frac{600}{r^2} &= 0 \\ \\ 4\pi r^3 - 600 &= 0 \\ \\ \pi r^3 &= 150 \\ \\ r &= \sqrt[3]{\frac{150}{\pi}} \approx 3.628\text{ cm}\end{aligned}$

Hence, the radius that minimizes the surface area will be about 3.628 centimeters.

Then the height will be:

$\displaystyle \begin{aligned} h&= \frac{300}{\pi\left( \sqrt[3]{\dfrac{150}{\pi}}\right)^2} \\ \\ &= \frac{60}{\pi \sqrt[3]{\dfrac{180}{\pi^2}}}\approx 7.25 6\text{ cm} \end{aligned}$

In conclusion, the dimensions that minimize the cost of materials for the cylinders have radii of about 3.628 cm and heights of about 7.256 cm.

7 0

3 years ago

The probability that a civil servant own a car is 1/6,if two civil servants are selected at random.find the probability that

Elodia [21]

Answer:

The data we have is:

the probability that a civil servant own a car is 1/6

Two civil servants are selected at random.

a) The probability that each own a car.

Ok, here we have two events:

Person 1 haves a car.

Person 2 haves a car.

The probability of each of those events is the same, 1/6.

P1 = 1/6

P2 = 1/6

Now, the probability of both events happening at the same time is equal to the product of the individual probabilities.

P = P1*P2 = (1/6)*(1/6) = 1/36.

b) Only one has a car.

Suppose that Person 1 has the car and Person 2 has not a car.

The probability for person 1 is 1/6.

And for person 2, is the negation of having a car:

So if we have prob of having a car = 1/6

Then the probability of not having a car is = 1 - 1/6 = 5/6.

Then we have:

P1 = 1/6

P2 = 5/6.

The joint probability is:

P = P1*P2 = (1/6)*(5/6) = 5/36.

But we also have the case where person 1 does not have a car, and person 2 does have one, then we have a permutation, and the actual probability is two times the obtained above.

P = 2*(5/36) = 10/36

4 0

3 years ago

A string is tied to the top of a plant to keep it stabilized. The plant is 5 feet tall and the string is connected to the ground

Rasek [7]

R = √(2² + 5²) = √29 = 5 and change. Simple Pythagorean calc. Draw a picture and you will see it.

4 0

2 years ago

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