1 tàu hỏa đi từ A đến B với quãng đường là 40km . Khi đi đến B , tàu dừng lại 20 phút rồi đi tiếp 30km đến C với vận tốc lớn hơn vận tốc khi đi từ A đến B là 5km/h . Tính vận tốc của tàu khi đi trên quãng đường AB . Biết thời gian kể từ khi tài xuất phát từ A đến khi tới C hết tất cả 2gio

Answers

Answer 1

Answer:

The speed from A to B is 40 km/h.

Step-by-step explanation:

Distance from A to B = 40 km

Distance from B to C = 30 km

Speed from A to B is v km/h

Speed fro B to C is v + 5 .

total time, t = 2 hours

Stopping time at B = 20 minutes

Let the time from A to B is t'.

[tex]t'=\frac{40}{v}[/tex]

Let the time from B to C is t''.

[tex]t''= \frac{30}{v+5}[/tex]

The total time is

[tex]\frac{40}{v}+\frac{30}{v+5}+\frac{20}{60}=2\\\\\frac{40 v + 200 + 30 v}{v^2 + 5 v}=\frac{10}{6}\\\\420 v + 1200 = 10 v^2 + 50 v\\\\10 v^2 -370 v - 1200 = 0 \\\\v^2 - 37v - 120 = 0 \\\\v^2 - 40 v + 3 v - 120 = 0 \\\\v(v - 40) + 3 (v - 40) = 0\\\\(v - 4)(v + 3) = 0\\\\v = 40 km/h or - 3 km/h[/tex]

Speed cannot be negative so the speed from A to B is 450 km/h.


Related Questions

1 + 2 + 3 + ... + 98 + 99 + 100

Answers

Answer:

101 + 102 + 103 + ... + 998 + 999 + 1000

Step-by-step explanation:

Answer:     5050

=====================================================

Explanation:

This series is arithmetic since the common difference is 1. In other words, we're adding 1 to each term to get the next one.

The quickest way to find the sum is to use the formula below

S = (n/2)*(a+b)

where n is the number of terms, 'a' is the first term, and b is the last (or nth) term. This formula only works for arithmetic series.

We can see that n = 100, a = 1 and b = 100, so....

S = (n/2)*(a+b)

S = (100/2)*(1+100)

S = 50*101

S = 5050

-----------

This can be confirmed by noticing that we have 100/2 = 50 pairs of terms. Pair up the terms such that 1 goes with 100, 2 goes with 99, 3 goes with 98, and so on.

We have these fifty sums

1+100 = 101

2+99 = 101

3+98 = 101

....

48+53 = 101

49+52 = 101

50+51 = 101

We have 50 copies of 101 being added, which leads to 50*101 = 5050

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

The slowest and most tedious way to confirm this is to type 1+2+3+...+98+99+100 into your calculator. The result should say 5050. Using a spreadsheet would be a better option instead of using a handheld calculator. I don't recommend this unless you need more proof that we end up with 5050 as the final answer.

The manager of a football team says the probability that the team will win the next match is 0.6 and the probability it will lose is is 0.1 Find the probability that the team will: a) not win b) not lose c) not draw

Answers

Answer:

A. 0.4

B.0.9

C.0.7

Step-by-step explanation:

Answers:

a)    0.4b)   0.9c)   0.7

===========================================

Explanation:

Part (a)

P(winning) = 0.6 is given

The probability of not winning is 1 - P(winning) = 1 - 0.6 = 0.4

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

Part (b)

P(losing) = 0.1 is given

The probability of not losing is 1 - P(losing) = 1 - 0.1 = 0.9

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

Part (c)

The probability of winning is 0.6 and the probability of losing is 0.1

This adds to 0.6+0.1 = 0.7, which must mean 0.3 is the probability of drawing (since 0.7+0.3 = 1)

So the probability of not drawing is 1 - P(draw) = 1 - 0.3 = 0.7, which is exactly the sum of the probabilities of winning and losing.

What is the value of x ?

Answers

Answer:

x = 20

Step-by-step explanation:

90 = 60 + (x + 10)

90 - 60 = x + 10

30 = x + 10

30 - 10 = x

20 = x

Answer:

x = 20

Step-by-step explanation:

From the diagram we see that ∠60° and ∠(x + 10)° are supplementary, therefore we know that the following is true...

60° + (x + 10)° = 90°

Now we just solve the equation and get the following...

60° + (x + 10)° = 90°

x° + 10° = 30°

x° = 20°

x = 20

Lee y contesta santiago quiere comer la mitad de un pastel y alba quiere un tercio del mismo pastel para repartirlo bien reducen las fracciones a comun denominador ¿en cuantas partes iguales deben dividir el pastel? ¿cuantas partes debe tomar cada uno?

Answers

Answer:

El pastel se debe dividir en 6 partes iguales, de las cuales Santiago debe tomar 3 y Alba debe tomar 2.

Step-by-step explanation:

Dado que Santiago quiere comer la mitad de un pastel y Alba quiere un tercio del mismo pastel, para repartirlo bien se deben reducir las fracciones a su común denominador. Así, para determinar en cuántas partes iguales deben dividir el pastel y cuántas partes debe tomar cada uno se deben realizar los siguientes cálculos:

Santiago = 1/2

Alba = 1/3

2 x 3 = 6

Santiago = 1/2 = 3/6

Alba = 1/3 = 2/6

Por lo tanto, el pastel se debe dividir en 6 partes iguales, de las cuales Santiago debe tomar 3 y Alba debe tomar 2.

Which side lengths form a right triangle?​

Answers

Answer:

[tex]\text{A. }3, \sqrt{27}, 6,\\\text{B. }8, 15, 17,\\\text{C. }5, 5, \sqrt{50}[/tex]

Step-by-step explanation:

All right triangles must follow the Pythagorean Theorem [tex]a^2+b^2=c^2[/tex] where [tex]c[/tex] is the hypotenuse of the triangle.

Verify:

[tex]3^2+\sqrt{27}^2=6^2\checkmark,\\8^2+15^2=17^2\checkmark,\\5^2+5^2=\sqrt{50}^2\checkmark[/tex]

Answer:

Option : A, B, C

Step-by-step explanation:

To make sure the lengths form sides of a triangle we use Pythagoras theorem:

Square of length of larger side = Sum of square of smaller sides.

[tex](A) 3, \sqrt{27}, 6: => 6^2 = 3^2 + (\sqrt{27})^2[/tex]

                        [tex]36 = 9 + 27\\36 = 36\\Satisfies \ Pythagoras \ Theorem[/tex]

[tex](B) 8, 15, 17 :=> 17^2 = 15^2 + 8^2[/tex]

                         [tex]289 = 225 + 64 \\289 = 289 \\Satisfies \ the \ condition[/tex]

[tex](C) 5, 5 , \sqrt{50} :=> (\sqrt{50})^2 = 5^2 +5^2\\[/tex]

                            [tex]50 = 25 + 25 \\50 = 50\\Satisfies \ the \ condition[/tex]

In a fruit cocktail, for every 25 ml of orange juice you need 30 ml of apple juice and 45 ml of coconut milk. What proportion of the cocktail is orange juice?
Give your answer as a fraction in its simplest form.

Answers

Answer:

1/4

Step-by-step explanation:

Add the three amounts:

25 ml + 30 ml + 45 ml = 100 ml

These three amounts make 100 ml of fruit cocktail.

The amount of orange juice is 25 ml.

The fraction of orange juice is

(25 ml)/(100 ml) = 25/100 = 1/4

Answer: 1/4

Given a circle with radius 4 cm, calculate (use π=3,14) the circumference, rounding off to two decimal places

Answers

Answer:

goodgydudufjdjdjdjdururirurur7rigjfifut

Step-by-step explanation:

goodghdhfudjdjsdhydydbsjshhdvrjeiid

G(x) = 8x - 9 for g(x) = 23

Answers

23=8x-9 It’s says g(x)=23 so put 23 where
+9 +9. The g(x) is on the equation.
First, add the 9
32=8x
/8 /8. Then, divide by 8.

4=x. And this should be your answer

Hope this helps! :)

Pls I need help with thia

Answers

Answer:

6

Step-by-step explanation:

Use Pythagorean Theorem to solve for the missing side:

[tex]a^2+b^2=c^2\\a^2+(7)^2=(\sqrt{85})^2\\a^2+49=85\\a^2=36\\\sqrt{a^2} =\sqrt{36}\\a=6[/tex]

number 1 and 2 pls help me

Answers

1) C.75

Explanation: 180-105=75

2) A.110

Explanation: 38+32+x=180, x=110
1. C. 75

2. A. 110
hope this helps

2 = n/3 what is n? what does n equal

Answers

Answer:

n = 6

Step-by-step explanation:

Given

2 = [tex]\frac{n}{3}[/tex] ( multiply both sides by 3 to clear the fraction )

6 = n

Answer:

n=6

Step-by-step explanation:

If you divided 6 and 3 you would get an answer of 2. So the equation is saying n/3 which is n divided by 3 would give an answer of 2.

12. You are driving on a major highway. If you drive in the left lane traffic is moving at 60mph, if you drive in the right lane, traffic is moving at 40mph. You can drive a maximum of 10 hours and need to go a minimum of 500 miles. Use the above information to answer part a and b below: 12a. Create a system of inequalities to model the potential travel time in 3 points each lane.
12b. If you want to spend an amount of time in each lane, would this allow you to reach your goal of driving 50 miles? just to fight your conclusion​

Answers

you are driving onajor highway 94 mp

1) Find 5 points on the line y = 3/5 x - 4 by picking 5 x values, plugging in, and getting 5 y values. You must pick x
values that result in INTEGER values for y. Show every step of the process, working vertically.
2) Graph the line from problem 1. You must use a straightedge on axes and line. Each line on the graph paper is one
unit. Put arrowheads on the line. Do NOT put numbers or hash marks on your graph. Show your 5 points clearly
3) Using the formula and working vertically, firid the slope between the points (-2,5) and (6,-7).
4) Identify the slope and y-intercept of the line y = -4/3 x + 4
5) Graph the line from problem #4 by plotting the y-intercept, and then using the slope to get a second point. All rules
from problem 2 apply here as well.

Answers

It’s 5 for sure it is

Determine whether the parallelogram is a rhombus, rectangle, square, or none. Explain.
Q(1,5), R(3,8), S(5,5), T(3,2)
Help ASAP

Answers

QRST is a rhombus

Let’s look at the diagonals
Length QS = sr(4^2 + 0) = 4
Length RT = sr(0 + 6^2) = 6
This means it cannot be a square or rectangle as they both have equal length diagonals.

QS is horizontal (y values same)
RT is horizontal (x values same)
This means it is a rhombus because diagonals are perpendicular and different lengths.

Squares have perpendicular diagonals of same length
Rectangles have diagonals of same length but not perpendicular

A store sells a certain tile for $2 per tile and a pint of paint for $3. A second store sells the same items for $1 per tile and $4 per pint of paint. Ari bought the same number of tiles and pints of paint at both stores, costing him $26 at the first store and $18 at the second store, before tax. Which system of equations can be used to find the number of tiles, x, and the number of pints of paint, y, that Ari bought at each store? A system of equations. 3 x plus 4 y equals 18. X plus 2 y equals 26. A system of equations. X plus 3 y equals 18. 2 x plus 4 y equals 26. A system of equations. 2 x plus 3 y equals 26. X plus 4 y equals 18. A system of equations. 3 x plus 2 y equals 26. 4 x plus y equals 18.

Answers

Answer:

2 x plus 3 y equals 26. X plus 4 y equals 18

Step-by-step explanation:

Number of tiles, = x

Number of pints of paint, = y

Store 1:

Cost per tile = $2 ; cost per pint = $3 ; total cost = $26

Store 2 :

Cost per tile = $1 ; cost per pint = $4 ; total cost = $18

System of equation:

2x + 3y = 26 - - - (1)

x + 4y = 18 - - - - - (2)

si 30 cuadernos cuestan 120 Bs ¿ cuantos costaran 18 cuadernos​

Answers

Ann’s s whence. Sank m. D sm n s

Lee ran a mile in 7 1/3 minutes. His friend Sam ran the same mile in 8 5/9 minutes. How many minutes faster did Lee run? (First answer will be the brainliest)

Answers

Answer:

1 2/9 minutes faster

Step-by-step explanation:

Take the larger number and subtract the smaller number

8 5/9 minutes - 7 1/3 minutes

Get a common denominator

8 5/9 - 7 1/3 *3/3

8 5/9 - 7 3/9

1 2/9 minutes faster

please help!

For each sentence, drag a word that will make the statement true.
Words may be used once or more than once.

Equilateral triangles are ___
acute triangles.

Scalene triangles are ___
acute triangles.

Right triangles are ___
acute triangles.

Obtuse triangles are ___
isosceles triangles.

Answers

Answer:

Equilateral triangles are sometimes

acute triangles.

Scalene triangles are never

acute triangles.

Right triangles are never

acute triangles.

Obtuse triangles are always

isosceles triangles.

5.0×10

1


1.50×10

5




= ?

help please last day of school

Answers

Answer:

5.0x10=50

1.50x10=15

Step-by-step explanation:

calculator

Find measure of angles B, E, D and C and the length of BC


Triangle ABC ~ Triangle DEF. Measure of angle A = 30 degrees and measure of angle F = 65 degrees. AB=20, DE = 35, EF= 28.

Answers

Answer:

< B = 180-30-65=85°

< E = 85°

< D = 30°

< C = 65°

BC = 20/35 × 28 = 16

Use the drop-down menus to complete the statements to match the information shown by the graph.

Answers

The right answer is 1/2

What is the solution to the equation 3(x - 1) – 2(2x + 1) = 8(x - 1)?

Answers

1. distribute and get:
3x - 3 - 4x - 2 = 8x - 8

2. simplify the first side of the equation
- x - 5 = 8x - 8

3.move all the x’s to one side
-5 = 9x - 8

4. completely isolate the 9x

3 = 9x

5. solve
x = 1/3

let me know if this is correct :)!

Answer pls………………………..

Answers

Answer:  Choice C.  [tex]3\sqrt{17}[/tex]

================================================

Work Shown:

[tex]d = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}\\\\d = \sqrt{(12-15)^2 + (-21-(-9))^2}\\\\d = \sqrt{(12-15)^2 + (-21+9)^2}\\\\d = \sqrt{(-3)^2 + (-12)^2}\\\\d = \sqrt{9 + 144}\\\\d = \sqrt{153}\\\\d = \sqrt{9*17}\\\\d = \sqrt{9}*\sqrt{17}\\\\d = 3\sqrt{17}\\\\d \approx 12.3693169\\\\[/tex]

I used the distance formula for those steps above.

The two points were (x1,y1) = (12,-21)  and (x2,y2) = (15,-9) but you could swap the order.

As an alternative route, you can plot the two points on the same xy grid. Then form a right triangle such that the hypotenuse is between the two points mentioned. The pythagorean theorem should lead you to the same answer as above. In fact, the distance formula is basically a modified version of the pythagorean theorem.

What is the factorization of 49b2 − 81?

Answers

Step-by-step explanation:

The factorisation of 49b^2 - 81 is (7b - 9)(7b + 9). This is because 49 and 81 are the squares of 7 and 9 respectively, so these must be multiplied together. b^2 is b x b. Finally, it must be -9 and +9 to make -81, because when the signs are the same the result is a positive number

Answer:

(7b - 9)(7b + 9)

Step-by-step explanation:

49b2 - 81

49 - 7 x 7

b2 - b x b

81 - 9 x 9

(a + b) (a - b) = a2 - b2

(7b - 9)(7b + 9)

Bruce and Krista are going to buy a new furniture set for their living room. They want to buy a couch, a coffee table, and a recliner. They have narrowed it down so that they are choosing between 4 couches, 5 coffee tables, and 9 recliners. How many different combinations are possible?

Answers

Answer:

180

Step-by-step explanation:

to work out all possibilities you multiple the amount of options.

4x5x9=180

Answer please fast
Do it now please, come on do it come on

Answers

Answer:

C 42yd

Step-by-step explanation:

Find the difference between one million and two hundred fifty thousand.
Express the difference in words in International and Nepali Systems.

Answers

Answer:

Step-by-step explanation:

[tex]One \ million = 1, 000, 000\\\\Two \ hundred \ and \ fifty \ thousand = 250, 000[/tex]

Difference between one million and two hundred and fifty thousand

[tex]1,000,000[/tex]  [tex]- \ 250,000[/tex] [tex]= 750000[/tex]

International  Number System,750,000: Seven Hundred  and Fifty Thousand

Nepalis Number System,7, 50,000 : Seven Lakh Fifty Thousand

Check all that are equivalent!

Answers

Answer:

3^6, 3^-4 * 3^10, 3^3 * 3^3, and (3*3) * (3*3*3*3) are the answers that are equivalent!

Step-by-step explanation:

These four are correct:-

3² × 3⁴ = 33-⁴ × 3¹⁰ = 3-⁴+¹⁰ = 33³ × 3³ = 3³+³= 3⁶(3×3)(3×3×3) = 3²× 3³= 3²+3⁴= 3⁶

Determine the value for x in the picture below.
Please help me

Answers

Given:

The figure of a right angle triangle.

A line segment intersect the two sides and parallel to third side of the triangle

To find:

The value of x.

Solution:

According to basic proportionality theorem, if a line segment intersect the two sides and parallel to third side of the triangle, then it divides the two sides proportionally.

Using basic proportionality theorem, we get

[tex]\dfrac{8}{20-8}=\dfrac{6}{x}[/tex]

[tex]\dfrac{8}{12}=\dfrac{6}{x}[/tex]

[tex]\dfrac{2}{3}=\dfrac{6}{x}[/tex]

On cross multiplication, we get

[tex]2\times x=6\times 3[/tex]

[tex]2x=18[/tex]

[tex]x=\dfrac{18}{2}[/tex]

[tex]x=9[/tex]

Therefore, the value of x is 9.

helpppppppppppppppppppppppppppppppppp!!!!!!!!!

Answers

The answer could be expressed as 2^8 because the product is 16!
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