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3 years ago

8

Twenty people get into an elevator in a hotel with seven floors, and all of them get off at some point. How many different possi

bilities exist for how the people could get off the elevator? (you can treat the people as indistinguishable for this problem, i.e., for example, if two people get off on the 4th floor, we don’t care which two people they are.)

1 answer:

Fittoniya [83]3 years ago

7 0

Answer:

140

Step-by-step explanation:

you multiply the amount of people by the amount of floors, 7x20=140

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Four brothers have ages which are consecutive even integers. If the product of the ages of the two middle brothers is 528, how o

exis [7]

Answer:

The oldest brother is of age $26$ years.

Step-by-step explanation:

As the age of four brothers are consecutive even integers.

We assume that the ages are $x,(x+2),(x+4),(x+6)$ as their respective ages.

And the age of the youngest brother $x$ yrs.

Age of the oldest brother $(x+6)$ yrs.

According to the question

Product of two middle brother that is $(x+2)(x+4) =528$

So we will arrange this in our equation and solve the quadratic.

$(x+2)(x+4) =528$

$x^{2}+4(x)+2(x)+8 =528$

$x^{2}+4(x)+2(x)+8-528=0$

$x^{2}+6(x)-520=0$

Solving the quadratic by using middle term splitting or directly with quadratic formula we can find the value of 'x' .

Here it is solved with quadratic formula:

Comparing with standard equation $ax^{2}+b(x)+c=0$ ,here $a=1,b=6\ and\ c=-520$ .

$x= \frac{-b \pm \sqrt{b^2-4ac} }{2a} = \frac{-6 \pm \sqrt{6^2-4\times \ (-520)} }{2\times 1}$

$x=20,-26$

We will work with the positive value of (x) so the the age of the youngest brother $=(x)=20$ yrs.

And the age of the the oldest brother $=(x+6)=(20+6)=26$ years.

The age difference is of $(26-20)=6$ years.

4 0

4 years ago

30 POINTSSS!!! The graph shows the relationship between the number of months different students practiced tennis and the number

balu736 [363]

Answer:

Part A:

The y-intercept is 3.25. This shows the point where the line intersects with the y-axis.

Part B:

The slope was found using the points (1,5) and (5,12). 5 -1 = 4, which is the run. 12- 5 = 7, which is the rise. 7 ÷ 4 = 1.75. This is the slope.

Input b and m;

y = 1.75x + 3.25

Now, input x;

y = 1.75(13) + 3.25

y = 22.75 + 3.25

y = 26

After 13 months of practice, the team can expect to win 26 matches.

6 0

3 years ago

3. Caleb has $25 to spend on prizes for a game at the school fair. Lip balm costs $1.25 each, and mini-notebooks cost $2.50 each

Snowcat [4.5K]

Answer:

linear equation in Standard form that can be used to determine how many of each prize Caleb can buy is $1.25x+ 2.50y = 25$

Step-by-step explanation:

Given:

Total cost spent on prizes for games = $25

Cost of one lip balm = $1.25

Cost of one mini notebook = $2.50

A) linear equation in STANDARD FORM that can be used to determine how many of each prize she can buy.

Let the number of lip balms be x and the number of mini note books be y. Then

$1.25x+ 2.50y = 25$

B. Graph the equation using x- and y- intercepts.

Now by trial and error method

$1.25(0)+ 2.50(10) = 25$

$1.25(2)+ 2.50(9) = 25$

$1.25(4)+ 2.50(8) = 25$

$1.25(6)+ 2.50(7) = 25$

$1.25(8)+ 2.50(6) = 25$

$1.25(10)+ 2.50(5) = 25$

$1.25(12)+ 2.50(4) = 25$

$1.25(14)+ 2.50(3) = 25$

$1.25(16)+ 2.50(2) = 25$

$1.25(18)+ 2.50(1) = 25$

$1.25(20)+ 2.50(0) = 25$

Thus Caleb can buy 0,2,4,6,8,9,10,12,14,1,6,18,20 lip balms and

0,1,2,3,4,5,6,7,8,9,10 mini note books respectively

Now plotting these value in the graph, we get the below graph

3 0

4 years ago

Helppp 20 POINTS!!!The radius of a circle is 4 inches. Using the formula A ≈ 3r2, what is the approximate area of the circle?

garik1379 [7]

Fyi area=pir^2 not 3r2
(oh, I see, you want to aprox pi=3, ok)

radius=4

3(4^2)=area
3(16)=area
48=area

answer is 48in^2

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3 years ago

What shape best describes the cross section cut at an angle to the base of a right rectangular prism?

Rufina [12.5K]

Answer:

right angle triangle

6 0

3 years ago