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3 years ago

PLEASE HELP! I'M STRUGGLING! WILL GIVE BRAINLIEST

Mathematics

2 answers:

Kisachek [45]3 years ago

8 0

Answer: 5/6

The complement of an event is basically the complete opposite.

If you define event A to be the event of selecting an R, then the complement of event A is not selecting R.

The probability of selecting R is 1/6 because there is 1 letter R out of 6 letters total. The complement of this is 5/6. You could count out 5 letters that aren't R, out of 6 total, or you can subtract 1/6 from 1 to get

1 - (1/6) = (6/6) - (1/6) = (6-1)/6 = 5/6

lianna [129]3 years ago

7 0

Answer:

1/6

Step-by-step explanation:

Since there is only 1 letter R in 6 options it is 1/6 (im not entirely sure)

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How to solve the question

Scorpion4ik [409]

You have the equations set up correctly. I will use r and b as the variables to make it easier to follow.

12r + 8b = 70
20r + 12b = 110

First let's solve one of the equations for one of the variables.

12r = 70 - 8b

$r = \frac{70-8b}{12}$

Now plug that in for r in the second equation.

$20( \frac{70-8b}{12})+12b = 110$

Simplify

$20(70-8b)+144b=1320$

$1400-160b+144b=1320$

$-16b = -80$

b = 5 grams

Now plug 5 in for b in one of the original equations to find r.

12r + 8(5) = 70

12r = 30

r = 2.5 grams

So the red marbles weigh 2.5 grams, and the blue marbles weigh 5 grams.

3 0

4 years ago

A study is performed in a large southern town to determine whether the average amount spent on food per four-person family in th

hoa [83]

Step-by-step explanation:

H0: u = 150

H1: u ≠ 150

Total sum = 15933.24

N = 100

Mean = 15933.24/100

= 159.3324

σ² = 25954.03 - (159.3324)²/100

σ² = 556.213

σ = √556.213

σ = 23.8162

Testing hypothesis

t = (bar x - u)/ σ/√n

= 159.3324-150/23.8162/√100

= 3.91

We will have a p value of 0.02

0.0002 < 0.01

We reject null hypothesis at 1% level of significance

C. Mean = 159.3324

Se= 2.3936

Df = 100-1 = 99

Critical value at 0.01 = +-2.626

T = x-u/s.e

= -2.626 =( x -150)/2.3936

When we cross multiply and solve this

X = 143.714 for the lower tail

2.626 = (x-159)/2.3936

= 156.286 for upper tail.

We therefore reject H0 at

Bar X <= 143.71

Bar X >= 156.286

At 10%

Critical t = 1.660

-1.660 = (x - 150)/2.3936

Solving this ,

X =146.02 at the lower tail

1.660 = (x-150)/2.3936

X = 153.97

We reject H0 at

X<= 146.03

X>=153.97

4 0

3 years ago

If there are 250 fish in the lake and 50 more are added each year write the linear equation

Anastasy [175]

Answer:

250x+50y is answer

Step-by-step explanation:

answer !!!!!!!!

8 0

3 years ago

Write an equation that represents “Eight more than the quotient of a number and two is fourteen.”

seropon [69]

Answer:

I think it's supposed to be 8x+2=14

5 0

4 years ago

20 points! Can someone do part A for me? I know how to do these questions I’m just a tad bit confused. :/

Serhud [2]

Revenue = (number of phones)(price of phones)

If Mobistar charges $80 per phone, then their revenue is

$r=800\times80=64,000$

If they instead charge $2 less per phone (so that $d=1$ ), or $78 per phone, then their revenue would be

$r=840\times78=65,520$

If they charge $4 less per phone ( $d=2$ ), then they make

$r=880\times76=66,880$

and so on. As the hint suggests, we can write the number of phones sold as an expression depending on the number of price decreases $d$ ; that is, for each price decrease, the number of phones sold increases by 40.

Similarly, the price per phone can be written in terms of $d$ , since the cost of a phone starts at a fixed $80 and decreases by $2 for each unit of $d$ . So total revenue can be written as

$r(d)=(800+40d)(80-2d)$

You can stop there, but you may be expected to write this in standard quadratic form, which is just a matter of expanding $r(d)$ .

$r(d)=64,000+1,600d-80d^2$

For the remaining parts:

(B) Writing in vertex form will help, as the name suggests. That's just a matter of completing the square. You have

$r(d)=-80d^2+1,600d+64,000$
$r(d)=-80(d^2-20d-800)$
$r(d)=-80(d^2-20d+100-100-800)$
$r(d)=-80((d-10)^2-900)$
$r(d)=72,000-80(d-10)^2$

which is to say the vertex of the parabola described by $r(d)$ occurs at (10, 72,000). The parabola "opens downward" (which we know because the sign of the leading (quadratic) term is negative), so the vertex is a maximum of the revenue function, which in turn means the most revenue the company can achieve will be achieved if $d=10$ , netting them $72,000. This translates to setting the price per phone to $80-2(10)=\$60$ .

4 0

4 years ago