What is this answer (please)

In how many ways can 7 people line if A needs to be first or last and B needs to be in the middle

12345 [234]

Answer:

Assuming person A and person B are part of the 7 people, there are 10 ways the 7 people can line up if A needs to be first or last and B needs to be in the middle.

Step-by-step explanation:

There are 2 places for A (first, last) and 5 places for B (anywhere but first or last). 2 x 5 = 10.

8 0

2 years ago

A rectangle has perimeter, P, length, land width, w. Which of the following represents lin

almond37 [142]

Answer:

$l=\frac{P}{2}-w$ .

Step-by-step explanation:

The perimeter of a rectangle is the sum of it's side lengths.

A rectangle has 4 sides where it's opposite sides are congruent.

So if one side has measurement w, then there is another side that has measurement w.

If there is one side that has measurement l, then there is another side that has measurement l.

So if you add w+w+l+l you get 2w+2l.

They are giving us that the perimeter is P, so P=2w+2l.

we are being asking to solve for l.

P=2w+2l

First step: Isolate term that contains the l, so get 2l by itself first.

We are going to subtract 2w on both sides giving us:

P-2w=2l

2l=P-2w

Now that we have 2l by itself it is time to perform the last step in getting l by itself.

Second step: Divide both sides by 2.

This gives us:

l=(P-2w)/2

You may separate the fraction like so:

$l=\frac{P-2w}{2}=\frac{P}{2}-\frac{2w}{2}=\frac{P}{2}-w$ .

I don't know your options but I have solve for l in terms of P and w

and got $l=\frac{P}{2}-w$ .

Please let me know if you have further questions with this problem.

4 0

3 years ago

5) You and a friend live 4 miles apart. You hear the sound of thunder 18 seconds before your friend hears it. Assuming sound tra

Leokris [45]

Answer:

see attached

Step-by-step explanation:

At 1100 ft per second for 18 seconds, the sound travels 19,800 ft, or 3.75 miles farther to my friend's house. The set of points that lie 3.75 miles farther from my friend's house than from my house form a hyperbolic curve. This is illustrated by the blue line in the attached graph. (My house is the red dot on the left; my friend's house is the red dot on the right.)

The lightning occurred somewhere on the blue curve.

___

If the lightning occurred on the line between our houses, it was 1/8 mile from my house and 3 7/8 mile from my friend's house. (That's close!)

_____

The formula for the curve in the graph is the distance formula applied to the set of points (x, y). It equates the difference of distance from the two houses to 3.75 miles. If one were to write the equation of the hyperbola in standard form, the equation would look a little different and a restriction would need to be applied so the formula would describe only one branch of the hyperbola.