I need help with #15 please

Using a phone card to make a long distance call costs a flat fee of $0.57 plus $0.31 per minute starting with the first

aliina [53]

Answer:

it's d

Step-by-step explanation:

multiply 0.31 by the amount of minutes used (27) and add the flat fee to it.

0.31×27+(0.57)= 8.94

7 0

2 years ago

The sum of the digits of a 2-digit number is 10. If 18 is added to the number, the digits of the new number are those of the ori

Aliun [14]

Answer:

46

Step-by-step explanation:

Let $(ab)$ represent a number with $a$ in the ten's position and $b$ is the one's position.

This means $(ab)$ actually has value of $10a+b$ .

We are given the sum of those digits of $(ab)$ is 10; this means $a+b=10$ .

It says if 18 is added to the number $(ab)$ , then the result is $(ba)$ .

So $(ab)$ has value $10a+b$ and

$(ba)$ has value $10b+a$ .

We are given then:

$(ab)+18=(ba)$

$10a+b+18=10b+a$

Subtract $10a$ on both sides:

$b+18=10b+a-10a$

Simplify:

$b+18=10b-9a$

Subtract $b$ on both sides:

$18=10b-b-9a$

$18=9b-9a$

Divide both sides by 9:

$2=b-a$

Rearrange by commutative property:

$2=-a+b$

So the system of equations we want to solve is:

$a+b=10$

$-a+b=2$

-------------------------Add equations together (this will eliminate the variable $a$ and allow you to go ahead and solve for $b$ :

$0+2b=12$

$2b=12$

Divide both sides by 2:

$b=\frac{12}{2}$

Simplify:

$b=6$

If $b=6$ and $a+b=10$ , then $a=4$ . $a=4$ since 4+6=10.

So the original number is (46).

18 more than 46 is 18+46=(64) which is what we wanted.

We also have the sum of 4 and 6 is 10 as well.

7 0

3 years ago

In the given figure find the value of x and y?<br>Show you works - Thank you!

Vaselesa [24]

<u>EXPLANATION</u><u>:</u>

In ∆ ABC , ∠ABC = 40°

∠CAB = x°
& ∠ACD = 50°

∠ACD is an exterior angle formed by extending BC to D

We know that

The exterior angle of a triangle formed by extending one side is equal to the sum of the opposite interior angles.

∠ACD = ∠CAB + ∠ABC

⇛50° = x° + 40°

⇛x° = 50°-40°

and

In ∆ ACD , AC = CD

⇛ ∠CDA = ∠CAD

Since the angles opposite to equal sides are equal.

Let ∠CDA = ∠CAD = A°

We know that

The sum of all angles in a triangle is 180°

In ∆ ACD,

∠CDA +∠CAD + ∠ACD = 180°

A°+A°+50° = 180°

⇛2A°+50° = 180°

⇛2A° = 180°-50°

⇛2A° = 130°

⇛A° = 130°/2

⇛A° = 65°

now,

∠CDA = ∠CAD = 65°

∠BAC + ∠CAD+y = 180°

Since angles in the same line

10°+65°+y = 180°

⇛75°+y =180°

⇛y = 180°-75°

<u>Answer</u><u>:</u> Hence, the value of “x” & “y” will be 10° and 105° respectively.

4 0

2 years ago

Question in the middle please

oksian1 [2.3K]

So it wants you to write two equations, one for the number of fruit and another for the money spent. gather your important information first:

20 fruits for $11.50
apples cost $0.50
bananas cost $0.75

let's do the cost equation first. it's $0.50 per apple, so 0.50a, and $0.75 per banana, so 0.75b. the total cost is $11.50. put all of this information together:

0.50a + 0.75b = 11.50 ... so, the cost of apples bought plus the cost of bananas bought equals 11.50

note what your variables stand for. a represents the number of apples, b represents the number of bananas. to write an equation for how many fruits bought, you simply have to add these two and set them equal to 20 (the total number of fruits bought).

a + b = 20
and your other equation
0.50a + 0.75b = 11.50

these are your two equations. to solve the system of equations, you first want to get one variable alone; the first equation will be easier.

a + b = 20
a = 20 - b

now take this equation and plug it into the second equation.
0.50(20 - b) + 0.75b = 11.50 ... you'll notice that you only have one variable left: b. solve for it. the first step is to distribute 0.50 to the parentheses
10 - 0.50b + 0.75b = 11.50 ... combine like terms
10 + 0.25b = 11.50 ... subtract 10
0.25b = 1.5 ... divide by 0.25
b = 6

6 bananas were purchased. plug this back into an equation to find out how many apples were purchased.

a + 6 = 20 ... subtract 6
a = 14

14 apples and 6 bananas were bought.

3 0

3 years ago

What is the area of a regular hexagon with a side length of 12 cm<br> With process please

ivanzaharov [21]

Look at the picture.

The area of the hexagon is equal six times the area of the <span>equilateral triangle.

The formula of the </span><span>equilateral triangle with the leg a:

$A_\Delta=\dfrac{a^2\sqrt3}{4}$

Therefore the formula of the area of the hexagon with a side lenght a is:

$A=6\cdot\dfrac{a^2\sqrt3}{4}=\dfrac{3a^2\sqrt3}{2}$

We have a = 12cm. Substitute:

$A=\dfrac{3\cdot12^2\sqrt3}{2}=\dfrac{3\cdot144\sqrt3}{2}=3\cdot72\sqrt3=216\sqrt3\ cm^2$
</span>

4 0

3 years ago