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4 years ago

Are the rational numbers closed under addition?

Mathematics

1 answer:

Mumz [18]4 years ago

7 0

Answer:

Integers: This set is closed only under addition, subtraction, and multiplication. Rational Numbers: This set is closed under addition, subtraction, multiplication, and division (with the exception of division by 0). Irrational Numbers: This set is closed for none of the operations (e.g., = 2, a rational number).

Step-by-step explanation:

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A concert hall is having a special

Tju [1.3M]

Answer:

Ummmmmmmmmm pls be more specific is the hall big or small is it public or private pls edit this and make it a question

Step-by-step explanation:

4 0

3 years ago

There are 48 students in a school play. The ratio of boys to girls is 5:7. How many boys are in the school play? Explain how you

mr Goodwill [35]

Boys: x
gilrs: y

From the text of the task:

$\left \{ {{\frac{x}{y}=\frac{5}{7}} \atop {x+y=48 \rightarrow x=48-y}} \right.$

Replacing x:

$\frac{48-y}{y}=\frac{5}{7}\\
\\
7(48-y)=5y\\
\\
336-7y=5y\\
\\
12y=336\\
\\
y=\frac{336}{12}=28$

So there are 28 girs and 20 boys

7 0

4 years ago

Read 2 more answers

Use the distance formula to determine the distance between (-8,10) and (-6,7)

hjlf

Answer:

Distance: $\sqrt{13}$ units

Step-by-step explanation:

The distance formula is $d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$ where:

$d$ is the distance between points $(x_1,y_1)$ and $(x_2,y_2)$
$(x_1,y_1)$ are the coordinates of the first point
$(x_2,y_2)$ are the coordinates of the second point

We are given that:

$(x_1,y_1)=(-8,10)$
$(x_2,y_2)=(-6,7)$

To determine the value of our distance, $d$ , we plug in our given information into the formula and solve for

$d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

$d=\sqrt{(-6-(-8))^2+(7-10)^2}$

$d=\sqrt{(-6+8)^2+(-3)^2}$

$d=\sqrt{(2)^2+(-3)^2}$

$d=\sqrt{4+9}$

$d=\sqrt{13}$

Therefore, the distance between $(-8,10)$ and $(-6,7)$ is $\sqrt{13}$ units.

See the attached graph for a visual.

5 0

3 years ago

If you invest 3,500 in a savings account that pays 4% simple interest how much will the new balance be after including interest?

garik1379 [7]

Answer:

New balance = 3640

Step-by-step explanation:

Given the following data;

Interest rate = 4% = 4/100 = 0.04

Principal = 3500

To find the new balance;

First of all, we would find the amount at the interest rate;

New amount = interest rate * principal

New amount = 0.04 * 3500

New amount = 140

Now, to find the new balance;

New balance = principal + new amount

New balance = 3500 + 140

New balance = 3640

8 0

3 years ago

The total amount of money earned by all three plumbers on Monday was $1,400. On Tuesday they earned a total of $1,660, and on We

Alekssandra [29.7K]

Set of equations that can be used to calculate rate for each plumber:
2A+8B+8C = 1,400 --- (1)
4A+7B+10C = 1,660 --- (2)
3A+9B+9C = 1,660 --- (3)
------------------------------------
2*(1) - (2)
------------------------------------
4A+16B+16C = 2,800
4A+7B+10C = 1,660 -
------------------------------------
9B+6C = 1,140 --- (4)
------------------------------------
3(2) -4(3)
-----------------------------------
12A+21B+30C = 4,980
12A+36B+36C = 6,600 -
-----------------------------------
-15B-6C = -1,620 --- (5)
------------------------------------
(4) + (5)
------------------------------------
9B+6C = 1140
-15B-6C = -1620 +
-------------------------------------
-6B = -480 => 6B = 480 => B = 480/6 = 80
-------------------------------------------------------
Using (4), 9(80)+6C = 1140
720+6C = 1140 => 6C = 1140-720 = 420 => C = 420/6 = 70
------------------------------------------------------------------------------
Using (1), 2A+8(80)+8(70) = 1400
2A+640+560 =1400 => 2A = 1400-640-560 = 200 => A = 200/2 = 100
----------------------------------------------------------------------------------------------
The rates are:
A = $100
B = $80
C = $70
--------------------------------
On Thursday, number of calls: A = 4 hrs, B = 6 hrs, C = 3 hrs
Money earned = 4*100+6*80+3*70 = $1,090

6 0

4 years ago

Read 2 more answers