He determined that the value of 6 in 76,345 is 100 times the value of 6 in 34,675. Part A: Is Lucas right? Part B: Explain why Lucas is right or wrong.

9514 1404 393

Answer:

  boat speed: (7t -95)/(6t² -110t +500)

  stream speed: (37t -345)/(6t² -110t +500)

Step-by-step explanation:

The relation between time, speed, and distance is ...

  time = distance/speed

The boat speed (b) is added to the stream speed (s) going downstream. The stream speed is subtracted going upstream. The given relations tell us ...

  25/(b-s) +44/(b+s) = t

  15/(b-s) +22/(b+s) = 5

This gives us 2 equations in 3 unknowns, so we can only provide a solution in terms of one of the unknowns. Since we are asked for the speeds, they will be provided in terms of t.

Subtracting the first equation from 2 times the second gives ...

  2(15/(b-s) +22/(b+s)) -(25/(b-s) +44/(b+s)) = 2(5) -(t)

  5/(b-s) = 10 -t

  5/(10 -t) = b -s

Substituting for b-s in the second equation gives ...

  15/(5/(10-t)) +22/(b+s) = 5

  30 -3t +22/(b+s) = 5

  22/(b+s) = 3t -25

  22/(3t -25) = b+s

Adding the equations for the sum and difference of speeds, we get ...

  (b-s) +(b+s) = 5/(10-t) +22/(3t -25)

  2b = (5(3t -25) +22(10 -t))/((10-t)(3t-25)) = (95 -7t)/((10-t)(3t-25))

  b = (7t -95)/(6t² -110t +500)

Subtracting the equations for sum and difference of speeds, we get ...

  (b+s) -(b-s) = 22/(3t -25) -5/(10 -t)

  2s = (22(10-t) -5(3t -25))/((10-t)(3t-25))

 s = (37t -345)/(6t² -110t +500)

__

The speed of the boat in still water is (7t -95)/(6t² -110t +500) km/h.

The speed of the stream is (37t -345)/(6t² -110t +500) km/h.

__

Note that these solutions only make sense for values of t between 25/3 and 345/37, approximately 8.33 < t < 9.32. For t=9 hours, the boat speed is 8 km/h and the stream speed is 3 km/h.

Answer:

Answer: 1/9

Step-by-step explanation:

(27^1/3 = 3

9^1/2 = 3

3^b

====

3^a

3^(b - a)

3^-2 = 1/9

1/9

Answer:

it can have any about 3 and up as long as it is a 2d shape and it has to have straight lines

Answer:

They all vary. All a polygon needs is straight sides, two dimensions, and equal length sides.

Step-by-step explanation:

Hope this helps!

Step-by-step explanation:

x+5Y=13...... 1

4x +7y=0..... 2

from eqn 1

x =13-5y

substitute into eqn 2

[tex]4(13 - 5y) + 7y = 0[/tex]

52-20y +7y=0

52-13y=0

52=13y

y=52÷13

y=4

substitute Y into eqn 2

x +5y=13

x + 5(4)= 13

x+ 20=13

x=13-20

x=-7

Answer:

We conclude that her students, on average, do not take 30 minutes on the quiz, contrary to what the textbook company states.

Step-by-step explanation:

We are given;

Population mean; μ = 30 minutes

Population standard deviation; σ = 3 minutes

Sample size; n = 10

Sample mean; x¯ = 25

Significance level = 5% = 0.05

Let's define the hypotheses;

Null hypothesis; H0: μ = 30

Alternative hypothesis: Ha: μ ≠ 30

Let's find the test statistic;

z = (x¯ - μ)/(σ/√n)

z = (25 - 30)/(3/√10)

z = -5.27

From online p-value from z-score calculator attached using, z = -5.27, significance level = 0.05, two tailed hypothesis, we have;

p < 0.00001

This is less than the significance level, and so we will reject the null hypothesis and conclude that Her students, on average, do not take 30 minutes on the quiz, contrary to what the textbook company stated.

Answer:

A. Her students, on average, do not take 30 minutes on the quiz, contrary to what the textbook company stated.

Answer:

radius

Step-by-step explanation:

hope this helps

Multiply by cost of a dvd by the number of dvds bought ( x) and add the shipping charge.

A) 33.44 = 9.95x + 3.59

Subtract 3.59 from both sides.

29.85 = 9.95x

Divide both sides by 9.95

X = 29.85/9.95

X = 3

They bought 3 dvds.

B) 33.49-3.59 = 29.85

29.85/9.95 = 3

C) the steps were the same but solving arithmetic you didn’t have to do steps on both sides of an equation.

Answer:

6 and 8

Step-by-step explanation:

Answer:

6 and 8

Step-by-step explanation:

Q1: 6 and 8

Q2: 8 and 12

Q3: 12 and 15

Q4: 15 and 20

Brainlist Pls!

Answer:

4 1/12

Step-by-step explanation:

2 1/3 x 1 3/4 = 7/3 x 7/4 = 49/12 = 4 1/12

Answer:

49/12

Step-by-step explanation:

2⅓ x 1¾ =

7/3* 7/4

49/12

Answer:

the first triangle is 10

the second triangle is 8

Step-by-step explanation:

1. the formula for this is a²+b²=c²

c is the missing side

add in the numbers and you get 8²+6²=c²

8² is 64 and 6² is 36. 64+36 = 100

then find the square root of 100, which is 10

2. the formula for this is c²-b²=a²

17² - 15² = a²

289-225 = 64

the square root of 64 is 8

Answer:

By 2020, there will be 1,147 species of birds left

Step-by-step explanation:

The general model for an exponential decrease is;

y = I(1 - r)^t

where in this case;

y is the number of bird species at a particular decade from the initial

I is the number of birds initially at 1990

r is the decrease percentage which is 1.5% per decade ; 1.5% = 1.5/100 = 0.015

t in this case will be the number of decades after the initial

Mathematically, a decade is 10 years

The difference between 2020 and 1990 is 30

The number of decades in 30 years is 30/10 = 3

so t will be 3 here

Substituting these values into the equation, we have

y = 1200(1-0.015)^3

y = 1200(0.985)^3 = 1,146.8

To the nearest whole number, this is 1,147

Answer:

D.

Step-by-step explanation:

Hope this helps

~R3V0

Answer: B

4c^2 - 16c - 1

Step-by-step explanation:

(3c2 - 8c + 5) + (c2 - 8c - 6).

remove parantheses.

3c2 - 8c + 5 + c2 - 8c - 6

add common factors

answer= 4c^2 - 16c - 1

Answer:

It doubled up is what you could say

Answer:

-5.2

Step-by-step explanation:

15.6 ÷ (-3) = -5.2

Answer:

c

Step-by-step explanation:

Think of it like this. When you convert a percent to a decimal, just put a decimal point before the number. For example, 40%. You would put . before 40, making it 0.40, and you don't need the zero, so it becomes 0.4. For something like 8%, you would first put a zero before the 8, and then put a period before the zero, like so: 8%= 08%=0.08

Answer:

infinite number of solutions

Answer:

Step-by-step explanation:

hello :

r+b=7... (*)

3.75r+2.75b=22.25.... (**)

use (*) :  r = 7 - b

put this value in (**) :

3.75(7 - b)+2.75b =  22.25

26.25 -375b +2.75b = 22.5

-375b +2.75b = 22.5 - 26.25

- b = -3.75

so : b  = 3.75

but : r = 7 - b

r = 7 - 3.75

r = 3.25

Answer:

The Fourth one

[tex]f(x) = {5}^{x} [/tex]

Step-by-step explanation:

I hope that is useful for you :)

Answer:

n=3

Step-by-step explanation:

To solve the equation divide both sides by 4.

I'm assuming that you want to find n...

Step-by-step explanation:

Hello! I believe the answer is A. 30+0.25p=60.

Elijah has to pay a facility charge which is 30$. So we can go ahead and write that down! He has 60$ to spend, but he has to pay $0.25 per paintball. So we write that as 30+0.25p=60!! If you have any questions comment doen below!

Answer:i think it A to

Step-by-step explanation: it is the only one correct

Answer:

72% increase

Step-by-step explanation:

688-400= 288 increase

288/400= 0.72

0.72x100=

72% increase

what do you mean bruv?

N O R M A L people put the answer up top

Answer:

8

Step-by-step explanation:

Let x be the number of people

12.5x + 13 < 125

x < 8.96

Max number of x is 8

Step-by-step explanation:

Given: f(x) = 3x^2 − 6x + 1.      x ∈ (-∞, ∞)

now differentiating f(x) w.r.t. x we get

f'(x) = 6x-6

equating it 0 we get

x = 1, which is a critical point

Now using second derivative test to check relative maxima or minima

f''(x) = 6 >0

⇒ x=1 is a relative minima.

also, x=1 f(1) = 3-6+1 = -2

Answer:

64

Step-by-step explanation:

Marcello sells coupon books to his neighbors

4 neighbors each buy 2 coupon books

Each book have 8 coupons

Therefore the total number of coupons that all neighbors will get can be calculated as follows

Each neighbor will get 16 coupon

Hence the whole neighbors will get

16×4

= 64 coupons

Answer:

75

Step-by-step explanation:

Note the location of the vertical line inside the box.  This locates the median.  Looking carefully, we see that this line hovers over 75 in the list of test scores.

The median is 75.  Look up "median" and "box plot" if you need more information.