Use the distributive property to find an expression equivalent to 6(s -7) -5 (4

Write the system of equations, then solve. SHOW ALL WORK!! please HELP! QUICK

uysha [10]

Answer:

3 30 page printers, 10 70 page printers

Step-by-step explanation:

x + y = 13

40x+70y = 820

Solving for y in first equation gives: y = 13 - x

Plug into second equation: 40x + 70(13 - x) = 820

40x + 910 - 70x = 820

-30 x = -90

x = 3

Plug into original equation: 3 + y = 13

y must = 10.

So, the company owns 3 thirty page presses, and 10 70 page presses,

5 0

2 years ago

Helpmehhhhhhhh plzzzzzzzzzzz

valentinak56 [21]

8 is 53.8
Cuz 66.93-6.57x2= 53.78 rounded to the nearest tenth 53.8

3 0

3 years ago

The College Board SAT college entrance exam consists of three parts: math, writing and critical reading (The World Almanac 2012)

Wittaler [7]

Answer:

Yes, there is a difference between the population mean for the math scores and the population mean for the writing scores.

Test Statistics = $\frac{Dbar - \mu_D}{\frac{s_D}{\sqrt{n} } }$ follows $t_n_- _1$ .

Step-by-step explanation:

We are provided with the sample data showing the math and writing scores for a sample of twelve students who took the SAT ;

Let A = Math Scores ,B = Writing Scores and D = difference between both

So, $\mu_A$ = Population mean for the math scores

$\mu_B$ = Population mean for the writing scores

Let $\mu_D$ = Difference between the population mean for the math scores and the population mean for the writing scores.

Null Hypothesis, $H_0$ : $\mu_A = \mu_B$ or $\mu_D$ = 0

Alternate Hypothesis, $H_1$ : $\mu_A \neq \mu_B$ or $\mu_D \neq$ 0

Hence, Test Statistics used here will be;

$\frac{Dbar - \mu_D}{\frac{s_D}{\sqrt{n} } }$ follows $t_n_- _1$ where, Dbar = Bbar - Abar

$s_D$ = $\sqrt{\frac{\sum D_i^{2}-n*(Dbar)^{2}}{n-1}}$

n = 12

Student Math scores (A) Writing scores (B) D = B - A

1 540 474 -66

2 432 380 -52

3 528 463 -65

4 574 612 38

5 448 420 -28

6 502 526 24

7 480 430 -50

8 499 459 -40

9 610 615 5

10 572 541 -31

11 390 335 -55

12 593 613 20

Now Dbar = Bbar - Abar = 489 - 514 = -25

Bbar = $\frac{\sum B_i}{n}$ = $\frac{474+380+463+612+420+526+430+459+615+541+335+613}{12}$ = 489

Abar = $\frac{\sum A_i}{n}$ = $\frac{540+432+528+574+448+502+480+499+610+572+390+593}{12}$ = 514

∑ $D_i^{2}$ = 22600 and $s_D$ = $\sqrt{\frac{\sum D_i^{2}-n*(Dbar)^{2}}{n-1}}$ = $\sqrt{\frac{22600 - 12*(-25)^{2} }{12-1} }$ = 37.05

So, Test statistics = $\frac{Dbar - \mu_D}{\frac{s_D}{\sqrt{n} } }$ follows $t_n_- _1$

= $\frac{-25 - 0}{\frac{37.05}{\sqrt{12} } }$ follows $t_1_1$ = -2.34

Now at 5% level of significance our t table is giving critical values of -2.201 and 2.201 for two tail test. Since our test statistics doesn't fall between these two values as it is less than -2.201 so we have sufficient evidence to reject null hypothesis as our test statistics fall in the rejection region .

Therefore, we conclude that there is a difference between the population mean for the math scores and the population mean for the writing scores.

8 0

3 years ago

Find the perimeter and area of a 4 m by 12 m rectangle.

Ann [662]

Answer:

P=32m

A=48 m^2

Step-by-step explanation:

if two shorter sides are 4m each and the two longer sides are 12 m

4+4+12+12 to find the total P

Area, time the LENGTH by WIDTH to find the squared meters in the rectangle .

4x12 = AREA

5 0

3 years ago

Find the vertical component given that R = 42 lb. and = 80. 41.36 7.29 59.45

valentina_108 [34]

Answer:

a

Step-by-step explanation:

3 0

3 years ago

Use the distributive property to find an expression equivalent to 6(s -7) -5 (4 - t)