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iogann1982 [59]

2 years ago

12

One end of a ladder 32 feet long is placed 10 feet from the outer wall of a building that stands on the ground level. How far up

the building to the nearest foot will the ladder reach?

1 answer:

ladessa [460]2 years ago

4 0

Answer:

30 ft

Step-by-step explanation:

This is a classic right triangle problem, where the length of the ladder represents the hypotenuse, where the ladder is lengthwise from the building is the base of the triangle, and what we are looking for is the height of the triangle. Pythagorean's Theorem will help us find this length.

$32^2-10^2=y^2$ so

1024 - 100 = y^2 and

y = 30.4 so 30 feet

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2.) Bob has two weekend jobs. Last weekend he made a total of $77 after

aalyn [17]

Answer:

Step-by-step explanation:

x= money earned per hour working as a cashier.

y=money earned per hour working delivering newspapers.

We propose the following system of equations:

5x + 4y =77

6x + 3y=78

We solve the system by reduction method:

-6*(5x+4y=77) ⇒ -30x-24y=-462

5*(6x+3y=78)⇒ 30x+15y=390

---------------------------

-9y=-72 ⇒ y=-72 /-9=8

Now, we get the value of "x" replacing the value of "y" by "8" in any part of the equation above.

5x + 4(8)=77

5x+32=77

5x=77-32

5x=45

x=45/5=9

therefore;

money earned per hour working as a cashier= $9/ hour

money earned per hour working delivering newspapers=$8/hour

3 0

2 years ago

Read 2 more answers

EXAMPLE 5 If F(x, y, z) = 4y2i + (8xy + 4e4z)j + 16ye4zk, find a function f such that ∇f = F. SOLUTION If there is such a functi

Valentin [98]

If there is such a scalar function <em>f</em>, then

$\dfrac{\partial f}{\partial x}=4y^2$

$\dfrac{\partial f}{\partial y}=8xy+4e^{4z}$

$\dfrac{\partial f}{\partial z}=16ye^{4z}$

Integrate both sides of the first equation with respect to <em>x</em> :

$f(x,y,z)=4xy^2+g(y,z)$

Differentiate both sides with respect to <em>y</em> :

$\dfrac{\partial f}{\partial y}=8xy+4e^{4z}=8xy+\dfrac{\partial g}{\partial y}$

$\implies\dfrac{\partial g}{\partial y}=4e^{4z}$

Integrate both sides with respect to <em>y</em> :

$g(y,z)=4ye^{4z}+h(z)$

Plug this into the equation above with <em>f</em> , then differentiate both sides with respect to <em>z</em> :

$f(x,y,z)=4xy^2+4ye^{4z}+h(z)$

$\dfrac{\partial f}{\partial z}=16ye^{4z}=16ye^{4z}+\dfrac{\mathrm dh}{\mathrm dz}$

$\implies\dfrac{\mathrm dh}{\mathrm dz}=0$

Integrate both sides with respect to <em>z</em> :

$h(z)=C$

So we end up with

$\boxed{f(x,y,z)=4xy^2+4ye^{4z}+C}$

7 0

2 years ago

7is subtracted from the quotient of 48 divided by th<br>e sum of 5 & difference of 11 and 8

kramer

Answer:

7-48=41

÷

5+11-8

bodmas

5+3=8

41÷8=5.125

5 0

2 years ago

Read 2 more answers

Jinghua hiked 4 1/2 miles through the woods in 2 1/4 hours. She hiked the return trip at the same average rate but by a differen

Anna007 [38]

Answer:

5 miles.

Step-by-step explanation:

Consider the question: Jinghua hiked 4 1/2 miles through the woods in 2 1/4 hours. She hiked the return trip at the same average rate but by a different route taking 2 1/2 hours. How many miles did Jinghua hike on the return trip ?

First of all, we will find Jinghua's speed using given information as:

$\text{Speed}=\frac{\text{Distance}}{\text{Time}}$

Convert mixed fractions into improper fractions:

$4\frac{1}{2}\Rightarrow \frac{9}{2}$

$2\frac{1}{4}\Rightarrow \frac{9}{4}$

$\text{Jinghua's speed}=\frac{\frac{9}{2}\text{ Miles}}{\frac{9}{4}\text{ Hours}}$

Using property $\frac{\frac{a}{b}}{\frac{c}{d}}=\frac{ad}{bc}$ :

$\text{Jinghua's speed}=\frac{9*4\text{ Miles}}{9*2\text{ Hours}}$

$\text{Jinghua's speed}=\frac{2\text{ Miles}}{\text{ Hour}}$

We know that distance is equal to the product of speed and time.

$\text{Distance}=\text{Speed}\times\text{Time}$

Since we have been given that Jingua hiked the return trip at the same average rate, so distance covered by her on return trip would be speed (2 miles her hour) times given time (2 1/2 hours).

$\text{Distance covered by Jingua on return trip}=\frac{2\text{ Miles}}{\text{ Hour}}\times 2\frac{1}{2}\text{ Hours}$

$\text{Distance covered by Jingua on return trip}=2\text{ Miles}\times \frac{5}{2}$

$\text{Distance covered by Jingua on return trip}=5\text{ Miles}$

Therefore, Jingua hiked 5 miles on her return trip.

8 0

2 years ago

Nick starts with 20 milligrams of a radioactive substance. The amount of the substance decreases by 12 each week for a number of

Gre4nikov [31]

Answer:

what the answer

Step-by-step explanation:

6 0

2 years ago