Help mathh PLEAEE HELP

A jar contains 8 red marbles and y white marbles. If Joan takes 2 random marbles from the jar, is it more likely that she will h

podryga [215]

Answer:

a) y </= 8 is not sufficient

b) y >/= 4 is sufficient (y is not less than 3.5)

Step-by-step explanation:

Number of Red marbles = 8

Number of white marbles = y

Total number of marbles in the jar = 8+ y

Let Pr(R) be the probability of picking red marbles

Let Pr(W) be the probability picking white marbles

Pr(R) = 8/ (8+y)

Pr(W) = 7/(7+y)

Pr(RR) = Pr(R1) * Pr( R2)

= 8/(8+y) * 7/(7+y)

Pr(RW) = Pr(R1) * Pr(W2) + Pr(W1) * Pr(R2)

= 2[Pr(R1) * Pr(W2)

= 2[8/(8+y) * y/(7+y)]

The probability of having 2 red is greater than one marble of each color.

Pr(RR) > Pr( RW)

8/(8+y) * 7/(7+y) > 2[8/(8+y) * y/(7+y)]

7/(7+y) > 2(y/(7+y)

7/y > 2

7/2 > y

3.5 > y

y < 3.5

Therefore;

a) y </= 8 is not sufficient

b) y >/= 4 is sufficient (y is not less than 3.5)

6 0

3 years ago

What is the answer to 11y+13=12x

kherson [118]

Answer:

36

Step-by-step explanation:

7 0

3 years ago

Alexis and Jessica are shopping. Alexis buys 4 pairs of pants and 3 necklaces and pays $216. Jessica buys 7 pairs of pants and 2

kkurt [141]

Step-by-step explanation:

let us keep the price of pants as x

and price of necklace as y

Simultaneous equations comes as follows:

4x + 3y = 216 for Alexis

7x + 2y = 300 for Jess

we'll make either x or y equal

here let's make y equal

2 ( 4x + 3y = 216)

3 ( 7x + 2y = 300)

8x + 6y = 432

21x + 6y = 900

21x - 8x = 900 - 432

13x = 468

x = $36

so a pant costs $36

And

3y = 72

y = $ 24

so a necklace costs $36

7 0

3 years ago

The sum of two numbers is -5. The difference is 13. What is the smaller number?

Alex73 [517]

Answer:

The smaller number is -9.

Step-by-step explanation:

Let x and y be the two unknown numbers.

Their sum is -5. Hence:

$x+y=-5$

Their difference is 13. Hence:

$x-y=13$

This yields a system of equations. We can solve this using elimination. Adding the two equations together:

$(x+y)+(x-y)=(-5)+(13)$

Simplify:

$2x=8$

Divide both sides by two. Thus:

$x=4$

Using either equation (I'll use the first):

$(4)+y=-5\Rightarrow y=-9$

So, our two numbers are 4 and -9.

The smaller number is -9.

6 0

3 years ago

Lim x tends to a now find x^1/3-a^1/3/x^1/2-a^1/2

blagie [28]

Answer: $\frac{a}{3}-\frac{2}{3}-\frac{a}{2}$

Step-by-step explanation:

$\lim _{x\to \:a}\left(\frac{x^1}{3}-\frac{\frac{a^1}{3}}{\frac{x^1}{2}}-\frac{a^1}{2}\right)$

$=\frac{a^1}{3}-\frac{\frac{a^1}{3}}{\frac{a^1}{2}}-\frac{a^1}{2}$

$=\frac{a}{3}-\frac{2}{3}-\frac{a}{2}$

4 0

3 years ago

Help mathh PLEAEE HELP​

Help mathh PLEAEE HELP