if motorist drove a distance of 90km at constant speed for the first 40km and then drove 30 km/hr faster for the rest of the journey if the journey took him one hour, his average speed for the first 40 km is​

Answers

Answer 1

Answer:

Step-by-step explanation:

The motorist drove at a distance of 90km at a constant speed for the first 40km, and then 20 km/hr faster for the rest of the journey.

The whole journey took him 1hr.

Let S denotes the average speed (in km/hr) for the first 40 km.

Hence we get the following relation,

40/S + (90 - 40)/(S + 20) = 1

or 50/(S + 20) = 1 - 40/S = (S - 40)/S

or (S + 20)(S - 40) = 50S or S^2 - 70S - 800 = 0 or (S - 80)(S + 10) = 0

or S = 80 (km/hr) [Ans]

[S cannot be negative value]


Related Questions

objectivity in the interpretation of data is referred to as

Answers

In philosophy, objectivity is a central concept that generally denotes an objective and impartial approach to something. The opposite is subjectivity.

That something is objectively true, an objective truth, means that it is true regardless of subjectivity. Objectivity is usually an ideal in connection with research, as the result is expected to be as independent of the researcher's opinions or ideas as possible.

Objectivity is often also emphasized as a basic ideal in journalistic work. An important question in philosophy is whether it is possible to experience something objectively.

Learn more in https://brainly.com/question/17978261

x^8+8x^7+15x^6−9x^5−72x^4−135x^3+8x^2+64x+120 Factor completely given the following factors: (x+5) and (x+3) There should be 6 factors (2 given, 2 binomials, and 2 trinomials.) show steps​

Answers

Answer:

(×+3)(×+5)(×2)(×-1) (×^2+2×+4)(×^2+×+)

Step-by-step explanation:

Where the given one is bolded the 2 binomials is italicized Ang the 2 trinomials is underlined

pa BRAINLEST pls

what is 8 x ( 4 x 2 ) = ?

Answers

Answer:

64

Step-by-step explanation:

4*2 is 8

Multiply 8*8

Answer:

the answer is 64

Step-by-step explanation:

8(4*2)

=8*8

=64

If their food and beverages cost $25.30 and there is an 8% meals tax, how much is the bill? Enter your answer to the nearest cent.A coffee ta

Answers

For the total multiply the amount by 1 + the meal tax:

25.30 x 1.08 = $27.32

Answer: $27.32

its urgent please. my assignment is due in like 30 minutes

Answers

Answer:

( iii)

a-x/a+x =b

a-x=b(a+x)

a-x=ab+ax

a-ab=ax+x

a-ab=x(a+1)

a-ab/a+1=x(a+1)/a+1

x=a-ab/a+1

x=a(1-b)/a+1

Find two integers whose sum is -3 and product is -18

Answers

Answer: -6, 3

[] Our two integers will be x and y

        With this in mind,

                 x + y = -3

                 x * y = -18

[] Let's think about the factors of -18

        Then we will think about which ones could add up to 3

                 1 & 18, 2 & 9, 3 & 6 are factors of 18 (one being negative results in -18)

                 Well 1 and 18 cannot make 3, same for 2 and 9, that leaves us with 3 and 6.

[] Last, we will test

        You can see our test shows this solution works!

                 -6 + 3 = -3

                 -6 * 3 = -18

Have a nice day!

  I hope this is what you are looking for, but if not - comment! I will edit and update my answer accordingly. (ノ^∇^)

- Heather

(X-2)(x+1)
Expand and simplify

Answers

☆Answer :

(x - 2)(x + 1) = ...

= x² + (-2 + 1)x + (-2•1)

= x² - x - 2

Difference between 42.4 and 3.74

Answers

Answer:

38.66

Step-by-step explanation:

Just need some help with this one

Answers

Answer:

y = -2/3x + 10/3

What is the equation of the line that passes through the point (-6,-2)and has a slope of 1/6

Answers

Answer:

y = 1/6x -1

Step-by-step explanation:

Use point-slope form: y - y₁ = m (x - x₁)

y - (-2) = 1/6 (x - (-6))

y + 2 = 1/6x + 1

y = 1/6x - 1

Answer:

[tex]y=\frac{1}{6}x-1[/tex]

Step-by-step explanation:

According to,

y = mx + c

They have already given the slope of the line.

That means they've given value for m

So,

m = [tex]\frac{1}{6}[/tex]

And now we have to find the value of c ( the intercept on the y axis) using (-6,-2)

Here,

 ( -6 , -2 )

   ↑    ↑

  ( x ,  y )

Let us find the c now.

y = mx + c

[tex]-2 =\frac{1}{6} *-6+c\\-2=\frac{-6}{6} +c\\-2=-1+c\\-2+1=c\\-1=c[/tex]

Now let's write the equation of the line like this

y = mx+ c

[tex]y=\frac{1}{6}x-1[/tex]

Hope this helps you.

Let me know if you have any other questions :-)

A store buys 14 sweaters for $154 and sells them for $448. How much profit does the store make per sweater?

Answers

Answer:

Profit = $21

Step-by-step explanation:

14 sweaters = $154

Cost of 1 Sweater = 154 ÷ 14

= $11

New Cost for 14 Sweaters = $448

New Cost of 1 Sweater = 448 ÷ 14

= $32

Profit Per Sweater = 32 - 11

= $21

Full Profit = 448 - 154

= $294

Answer:

21

Step-by-step explanation:

21

10.
Identify the vertex of the parabola.



A. (−1, 0)

B. (0, −1)

C. (1, 0)

D. (0, 1)

Answers

Answer:

C. (1, 0)

Step-by-step explanation:

1,0 should be the vertex for this parabola

1,0 should be the correct answer

Which of the following travel in waves? Select all that apply.

1. Air
2. Light
3. Scent
4. Sound

Answers

4. Sound I think correct answer.

Answer:

Sound and Light

Step-by-step explanation:

Just did this and got it right!!

Hope it helps you!!!  :)

1. Write the following statements in the from of equations. a. One third of a number plus 7 is 26
pls tell step by step ​

Answers

Answer:

1/3x+7=26

Step-by-step explanation:

1/3 of a number which could anything so mark as X

add 7

equals 26

1/3x+7=26

I need help..............

Answers

Answer: Choice D

Explanation:

The commutative property of addition is A+B = B+A. We can add two numbers in any order. For example: 2+3 = 3+2 since both sides result in 5.

The idea applies to fractions as well. In choice D, the fractions 3/5 and 2/3 swap places so that we can group the 1/3 and 2/3. From there, the 1/3 and 2/3 combine to 1 and that's how we end up with the mixed number 1 & 3/5.

i need answers thank you

Answers

Answer:

A

Step-by-step explanation:

so i just added a similar question but the explanation was complicated so me and my mates need help with this one as well

Answers

Answer:

Y = -X + 9

Step-by-step explanation:

yeah-ya....... right?

Which expression can go in the blank to make the equation true?
-4.5 + 4.4 + = 0
A. -6.7 + 6.8 B. -6.7 + ( - 6.6) C. 7.2 + ( -7.2) D. 7.2 + (-7.3)

Answers

we have -4.5 + 4.4 + x = 0

<=> -0.1 + x = 0

<=> x = 0.1 ( P/s: x is the answer to fill in the blank )

Now look in the answer below we have :

+) A. -6.7 + 6.8 = 0.1 (S)

+) B. -6.7 +(-6.6) = -13.3 (NS)

+) C. 7.2 + (-7.2) = 0 (NS)

+) D. 7.2 + (-7.3) = -0.1 (NS)      ( P/s: NS : not selected , S : selected )

So A is the correct answer

Ok done. Thank to me :>

Answer:it is D

Step-by-step explanation:

Simplify 38 - 32
-
A. 34
B. 36
c. 310
D. 3-6

Answers

Answer:

38 - 32 = 6

Step-by-step explanation:

subtract the question

help me with this please and thank you !!

Answers

Answer:

I hope this helps.

PLS HELP!!!!!
I WILL PUT BRAINLIEST!!!!!!

Which of these graphs represents a function?

Answers

Answer:

X

Step-by-step explanation:

Suppose the voltage in an electrical circuit varies with time according to the formula V(t) = 40 sin(t) for t in the interval [0,].

The numerical value of the mean voltage in the circuit is

Answers

The numerical value of the mean voltage is 25.47 V

To find the numerical value of the mean voltage, V of V(t) = 40 sin(t), we integrate V(t) with respect to t over the interval [0.π]

So,

[tex]V = \frac{1}{\pi } \int\limits^\pi _0 {V(t)} \, dt \\V = \frac{1}{\pi } \int\limits^\pi _0 {40sint} \, dt \\V = \frac{1}{\pi } [-40cost]_{0}{\pi } \\V = \frac{1}{\pi } -[40cos\pi - 40cos0]\\\\V = \frac{1}{\pi } (-[40 X (-1) - 40 X 1})\\V = -\frac{1}{\pi } [-40 - 40]\\V = \frac{80}{\pi } \\V = 25.465 V[/tex]

V ≅ 25.47 V

So, the numerical value of the mean voltage is 25.47 V

Learn more about mean volatage here:

https://brainly.com/question/17928028

1. Which set of ordered pairs shows a functional relationship? *

25 points

a(4,-4) (4,4) (6,-6) (6,6)

b(3,8) (5,12) (7,17) (3,12)

c(2,6) (4,12) (6,18) (8,24)

d(3,-6) (5,-10) (3,-10) (6,-12)

Answers

Answer:

C

Step-by-step explanation:

X's go up by 2, and Y's go up by 6

Evaluate the formula χ2=
(n−1)s2
σ2 when σ=3.32​, n=38​, and s=3.36.

Answers

Answer:

Step-by-step explanation:

Enter the numbers in order from greatest to least,
- 14.6, -2.7, -10
please help!!

Answers

Answer:

-2.7, -10, -14.6

Step-by-step explanation:

[tex]5(x+3)=6(\frac{12+x}{2} } )\\[/tex]
find x please

Answers

Answer:

x=21/2

Step-by-step explanation:

5(x+3)=6(12+x/2)

Distribute the 5.

5x+15=6(12+x/2)

Reduce the numbers with the greatest common factor 2.

5x+15=3(12+x)

Distribute the 3.

5x+15=36+3x

Move the variable to the left-hand side and change the sign.

5x+15-3x=36

Collect like terms.

2x=36-15

2x=21

Divide 2 on both sides

x=21/2

Hope this helps :)

Answer:

x = 10.5

Step-by-step explanation:

5(x + 3) = 6( [tex]\frac{12+x}{2}[/tex]) ← distribute parenthesis on both sides

5x + 15 = [tex]\frac{72+6x}{2}[/tex] = 36 + 3x ( subtract 3x from both sides )

2x + 15 = 36 ( subtract 15 from both sides )

2x = 21 ( divide both sides by 2 )

x = 10.5

Which of the ordered pairs is a solution to the system of inequalities?

y ≥ 3

y > x

(-3, 2)
(2, 3)
(-4, 3)
(0, 0)

Answers

I think it’s the 2 and 3 one

Sorry if it’s wrong

DUE IN 2 HOURS HELP QUICK! I WILL GIVE U BRAINLIEST

Answers

3 x 3 = 9, 3 x 3 = 9, 9 x 9 = 81
A is 81

7 x 7 x 7 x 7 = 2,401
2,401 x 7 = 16,807
B is 16,807

10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 = 1000000000

10 x 10 x 10 x 10 x 10 x 10 x 10 = 10000000

1000000000/ 10000000 = 100

C is 100

5 x 5 x 5 x 5 x 5 x 5 x 5 x 5 = 390,625
390,625/ 5 = 78125
D is 78,125

Answer:

see explanation

Step-by-step explanation:

Using the rules of exponents

[tex]a^{m}[/tex] × [tex]a^{n}[/tex] = [tex]a^{(m+n)}[/tex]

[tex]a^{m}[/tex] ÷ [tex]a^{n}[/tex] = [tex]a^{(m-n)}[/tex]

(a)

3² × 3² = [tex]3^{(2+2)}[/tex] = [tex]3^{4}[/tex]

(b)

7 × [tex]7^{4}[/tex] = [tex]7^{(1+4)}[/tex] = [tex]7^{5}[/tex]

c)

[tex]10^{9}[/tex] ÷ [tex]10^{7}[/tex] = [tex]10^{(9-7)}[/tex] = 10²

(d)

[tex]5^{8}[/tex] ÷ 5 = [tex]5^{(8-1)}[/tex] = [tex]5^{7}[/tex]

subtract. write your answer as a fraction in simplest form. 5/9 - 2/9 = what​

Answers

Answer:

[tex] \frac{5}{9} - \frac{2}{9} = \frac{3}{9} [/tex]

hope helpful <3

Answer:

3/9

Step-by-step explanation: don't think of it as a fraction just subtract the top 2 numbers and you would get 3/9 in the simplest form is 1/3

Li enters a competition to guess how many jelly beans are in a jar.
Li’s guess is 345 jelly beans.
The actual number of jelly beans is 300
.What is the percent error of Li’s guess?

Answers

Answer:

15% 15%

Step-by-step explanation:

it was correct for me

The percent error of Li’s guess is 15%

What is the absolute error?

"It is the absolute difference between an observed value and the actual value."

What is the relative error?

"It is the ratio of the absolute error of the measurement to the actual value."

What is the percent error?

"It is the relative error multiplied by 100."

For given example,

Li’s guess is 345 jelly beans.

observed value (E) = 345

The actual number of jelly beans is 300

actual value (A) = 300

So, the absolute error is,

Absolute error = |E - A|

                        = | 345 - 300|

                        = 45

Now, we find the relative error of Li's guess.

Relative error = 45 ÷ 300

Relative error = 0.15

The percent error is,

0.15 × 100 = 15%

Therefore, the percent error of Li’s guess is 15%

Learn more about the percent error here:

brainly.com/question/3670306

#SPJ2

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