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2 years ago

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Suppose that electricity for the Lopez family toaster cost Ghc8.00 per hour. How much money will the Lopez family pay per year i

f they use the toaster 3 hours per week

1 answer:

aivan3 [116]2 years ago

8 0

The Answer is 1248 they should pay

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At a hardware store, each wooden plank costs $3.57. How much do 12 planks cost?

777dan777 [17]

To find this answer, we need to multiply 3.57 by 12.
$3.57 * 12 = 42.84$
Therefore, 12 planks will cost $42.84.

5 0

3 years ago

Read 2 more answers

The first gardener can finish the job in 6 hours, and the second gardener can do the same job in 7 hours. How long it will take

marissa [1.9K]

If the first gardener can finish the job in 6 hours, it means that every hour he completes 1/6 of the job.

By the same logic, the second gardener completes 1/7 of the job per hour.

So, if they work together, they complete

$\dfrac{1}{6}+\dfrac{1}{7}=\dfrac{7+6}{42}=\dfrac{13}{42}$

of the job per hour.

So, after 42/13 of a hour, they'll complete the job. Since one hour is made of 60 minutes, 42/13 of a hour is

$\dfrac{42}{13}\cdot 60 \approx 194$

So, it will take them about 194 minutes to finish the job, i.e. about 3 hours and 14 minutes.

8 0

3 years ago

What is 4x+3y+2z and 3x+5y+3z?

My name is Ann [436]

Answer:

Step-by-step explanation:

7x + 8y + 5z

I put the equations in parentheses, assuming that I would be adding both of the equations together. Then, I removed them and combined the like terms. I used two calculators to check my answer, and this should be correct.

6 0

3 years ago

Read 2 more answers

the surface area of earth is about 196.9 million square miles. The land area is about 57.5 million square miles, and the rest is

kow [346]

Answer: 29.2%

Step-by-step explanation:

The total surface area is 196.9 million square miles and out of this, land occupies 57.5 million square miles.

The probability that a meteorite would hit land is the percentage of and out of the entire planet area:

= Land area/ Total earth surface area

= 57.5/ 196.9

= 29.2%

8 0

3 years ago

Surface integrals using an explicit description. Evaluate the surface integral \iint_{S}^{}f(x,y,z)dS using an explicit represen

Jobisdone [24]

Parameterize $S$ by the vector function

$\vec r(x,y)=x\,\vec\imath+y\,\vec\jmath+f(x,y)\,\vec k$

so that the normal vector to $S$ is given by

$\dfrac{\partial\vec r}{\partial x}\times\dfrac{\partial\vec r}{\partial y}=\left(\vec\imath+\dfrac{\partial f}{\partial x}\,\vec k\right)\times\left(\vec\jmath+\dfrac{\partial f}{\partial y}\,\vec k\right)=-\dfrac{\partial f}{\partial x}\vec\imath-\dfrac{\partial f}{\partial y}\vec\jmath+\vec k$

with magnitude

$\left\|\dfrac{\partial\vec r}{\partial x}\times\dfrac{\partial\vec r}{\partial y}\right\|=\sqrt{\left(\dfrac{\partial f}{\partial x}\right)^2+\left(\dfrac{\partial f}{\partial y}\right)^2+1}$

In this case, the normal vector is

$\dfrac{\partial\vec r}{\partial x}\times\dfrac{\partial\vec r}{\partial y}=-\dfrac{\partial(8-x-2y)}{\partial x}\,\vec\imath-\dfrac{\partial(8-x-2y)}{\partial y}\,\vec\jmath+\vec k=\vec\imath+2\,\vec\jmath+\vec k$

with magnitude $\sqrt{1^2+2^2+1^2}=\sqrt6$ . The integral of $f(x,y,z)=e^z$ over $S$ is then

$\displaystyle\iint_Se^z\,\mathrm d\Sigma=\sqrt6\iint_Te^{8-x-2y}\,\mathrm dy\,\mathrm dx$

where $T$ is the region in the $x,y$ plane over which $S$ is defined. In this case, it's the triangle in the plane $z=0$ which we can capture with $0\le x\le8$ and $0\le y\le\frac{8-x}2$ , so that we have

$\displaystyle\sqrt6\iint_Te^{8-x-2y}\,\mathrm dx\,\mathrm dy=\sqrt6\int_0^8\int_0^{(8-x)/2}e^{8-x-2y}\,\mathrm dy\,\mathrm dx=\boxed{\sqrt{\frac32}(e^8-9)}$

5 0

3 years ago