help me please its confusing neeed help

Answer:

System of equations:

20x + 30y = 650

x + y = 25

Time underwater = 10 hours

Time at the surface = 15 hours

Step-by-step explanation:

Let x = time underwater at 20 km/h.

Let y = time on the surface at 30 km/h.

speed = distance/time

distance = speed * time

distance underwater: 20x

distance on the surface: 30y

total distance: 650

20x + 30y = 650

total time: x + y

total time: 25

x + y = 25

20x + 30y = 650

x + y = 25

20x + 30y = 650

-20x - 20y = -500

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

          10y = 150

              y = 15

x + y = 25

x + 15 = 25

x = 10

Answer:

40 books

Step-by-step explanation:

s = Stella's books

t = Tina's books

Given:

s = 5t

s - 16 = t + 16

Plug first equation into second:

5t - 16 = t + 16

4t = 32

t = 8 books

s = 5t = 40 books

((Check: 40 - 16 = 24 = 8 + 16 ✔ ))

Answer:

B

Step-by-step explanation:

there are four girls in total, and Martina is most probably a girl too. only 1 girl out of the four girls will be chosen so probability is 1/4

Answer:

-1

Step-by-step explanation:

im pretty sure its right

sry if it not good luck!!

Answer:

0

Step-by-step explanation:

zero is not a natural number,it is a whole number

Answer:

0

Step-by-step explanation:

Natural numbers are all positive whole numbers starting at 1 to infinity. So, 0 isn't a natural number.

I'm pretty sure you are :)

Answer:

5000

Step-by-step explanation:

Answer:

Số tien:S =150000+(x-10)14000

Step-by-step explanation:

Answer:

A' (-6,3)

B' (-3,0)

C' (-7,1)

Answered by GAUTHMATH

Answer:

A -6, 3

C -7 1

B -3,0

Step-by-step explanation:

Step-by-step explanation:

The key to solve this problem is using ratios and proportions.

The key to solve this problem is using ratios and proportions.Ratio is the relationship between two numbers, defined as the quotient of one number for the other. So: The ratio between two numbers a and b is the fraction a/b and it is read a to b. This reason can also be written a : b.

The key to solve this problem is using ratios and proportions.Ratio is the relationship between two numbers, defined as the quotient of one number for the other. So: The ratio between two numbers a and b is the fraction a/b and it is read a to b. This reason can also be written a : b.Given two reasons a/b and c/d we say that they are in proportion if a/b = c/d. The terms a and d are called extremes while b and c are the means. In every proportion the product of the extremes is equal to the product of the means: a.d = b.c

The key to solve this problem is using ratios and proportions.Ratio is the relationship between two numbers, defined as the quotient of one number for the other. So: The ratio between two numbers a and b is the fraction a/b and it is read a to b. This reason can also be written a : b.Given two reasons a/b and c/d we say that they are in proportion if a/b = c/d. The terms a and d are called extremes while b and c are the means. In every proportion the product of the extremes is equal to the product of the means: a.d = b.cA student uses the ratio of 4 oranges to 6 fluid ounces of juice to find the numbers of oranges needed to make 24 fluid ounces of juice.

The key to solve this problem is using ratios and proportions.Ratio is the relationship between two numbers, defined as the quotient of one number for the other. So: The ratio between two numbers a and b is the fraction a/b and it is read a to b. This reason can also be written a : b.Given two reasons a/b and c/d we say that they are in proportion if a/b = c/d. The terms a and d are called extremes while b and c are the means. In every proportion the product of the extremes is equal to the product of the means: a.d = b.cA student uses the ratio of 4 oranges to 6 fluid ounces of juice to find the numbers of oranges needed to make 24 fluid ounces of juice.

The key to solve this problem is using ratios and proportions.Ratio is the relationship between two numbers, defined as the quotient of one number for the other. So: The ratio between two numbers a and b is the fraction a/b and it is read a to b. This reason can also be written a : b.Given two reasons a/b and c/d we say that they are in proportion if a/b = c/d. The terms a and d are called extremes while b and c are the means. In every proportion the product of the extremes is equal to the product of the means: a.d = b.cA student uses the ratio of 4 oranges to 6 fluid ounces of juice to find the numbers of oranges needed to make 24 fluid ounces of juice. The error in the student's work was that they reversed the reason, 24/16 instead of 16/24.

Answer:

B

Step-by-step explanation:

It opens downwards, so the parabola is negative. This also means the vertex of the parabola is the highest point, therefore it is a maximum.

Answer:

192

Step-by-step explanation:

Apply the geometric mean formula to solve for x, which is the altitude of the right triangle.

The formula is:

h = √(mn)

h = x = ?

m = 144

n = 400 - 144 = 256

Substitute

h = √(256*144)

h = √36,864

h = 192

Therefore, x = 192

Answer:

Its 2.5 percent ladd enjoy

Step-by-step explanation:

Answer:

2 per team and 2 left

Step-by-step explanation:

10 can't split into 4 evenly so, you can only give 2 to each team causing there to be 2 left.

4*2 = 8

10-8 = 2

Answer:

A. AG = 2 × GD

F. GE = (1/2) × BG

Step-by-step explanation:

The given point G on triangle ΔABC, which is the point of intersection of the medians of the triangle, is the centroid of the triangle

The centroid divides each median line in the ratio 2:1, therefore, we have;

The length of AG = 2 × GD, CG = 2 × GF, and BG = 2 × GE

∴ GE = (1/2) × BG

Therefore, the correct options are;

A. AG = 2 × GD, and F. GE = (1/2) × BG

Answer:

True

Step-by-step explanation:

Any two points are always collinear because you can always connect them with a straight line. Three or more points can be collinear, but they don't have to be. ... Coplanar points: A group of points that lie in the same plane are coplanar. Any two or three points are always coplanar.

Answer:

-19

Step-by-step explanation:

5v+3w

Let v = -5 and w=2

5(-5) + 3(2)

Multiply first

-25 + 6

The add

-19

1. Evaljate 5v +3w for v = -5 and w = 2

plug-in

5(-5) +3(2)

-25 +6

Answer: -19

2. Simplify the expression 8(e -1) + 2(e -1)

Distribute

8(e -1) + 2(e -1)

8e -8 + 2e -2

10e -10

Answer:  10e -10

Answer:

8x^2-1+3^2

Step-by-step explanation:

Answer:

C

Step-by-step explanation:

As the legs and hypotenuse are same, these triangles are congruent by HL congruency

We know

[tex]\boxed{\sf cos\Theta=\dfrac{b}{h}}[/tex]

[tex]\\ \sf\longmapsto cos22=\dfrac{x}{47}[/tex]

[tex]\\ \sf\longmapsto 0.9=\dfrac{x}{47}[/tex]

[tex]\\ \sf\longmapsto x=47(0.9)[/tex]

[tex]\\ \sf\longmapsto x=42.3[/tex]

Answer:

<2 = 75°

<3 = 75°

Step-by-step explanation:

<2 = <6

2x+15 = 45+x

or, 2x-x = 45-15

or, x = 30

so, <2 = 30×2+15 = 75

<6 = 45+30 = 75

Answered by GAUTHMATH

Answer:

[tex] ({a + b})^{2} [/tex]

[tex](a + b)(a + b)[/tex]

[tex] {a}^{2} + 2ab + {b}^{2} [/tex]

hope this help you

Answer:

0.9

Step-by-step explanation:

100,000 in 90,000

Answer:

f(- 1) = 3

Step-by-step explanation:

To evaluate f(- 1) substitute x = - 1 into f(x) , that is

f(- 1) = (- 1)² - 5(- 1) - 3 = 1 + 5 - 3 = 3

Answer:

Step-by-step explanation:

Answer:

X>3

Step-by-step explanation:

-2.5x +5 < -2.5

-2.5x < -2.5-5

-2.5x< -7.5

X> -7.5/-2.5

X>3

Answer:

∠ 3 = 90°

Step-by-step explanation:

∠ 3 and ∠ 4 are adjacent angles on a straight line and sum to 180° , then

∠ 3 + ∠ 4 = 180°

∠ 3 + 90° = 180° ( subtract 90° from both sides )

∠ 3 = 90°

Answer:

ST = 8 m

SU = 7 m

m∠Q = 75°

m∠S = 59°

m∠R = 46°

m∠U = 46°

Step-by-step explanation:

The given parameter are;

ΔPQR is congruent to ΔSTU

In ΔPQR, m∠P = 59°, PR = 8 m, PQ = 7 m

In ΔSTU, m∠T = 75°

By Side-Angle-Side rule of congruence, and given that m∠P ≠ m∠T, we can have;

m∠S ≅ m∠P, by Congruent Parts of Congruent Triangles are Congruent, CPCTC

ST ≅ PR, SU ≅ PQ, m∠Q ≅ m∠T, m∠U ≅ m∠R

Therefore;

ST = PR = 8 m

ST = 8 m

SU = PQ = 7 m

SU = 7 m

m∠Q = m∠T = 75°

m∠Q = 75°

m∠S = m∠P = 59°

m∠S = 59°

m∠U = m∠R = 180 - (75° + 59°) = 46°

m∠R = 46°

m∠U = 46°.

Answer:

(10/y+13)-3

(10/5+13)-3

(2+13)-3

15-3

12

I hope this will help you

Answer:

3

Step-by-step explanation:

(2/3)/(2/9) = (2/3) * (9/2) = 3