Ask question

Ask question

All categories

2 years ago

8

Alex and Nick collect baseball cards. Alex has three more than twice as many cards as Nick. Together they have 27 cards. How man

y cards does Alex have?

2 answers:

jek_recluse [69]2 years ago

5 0

Answer:

21

Step-by-step explanation:

Blizzard [7]2 years ago

4 0

Answer: 21

Step-by-step explanation:

You might be interested in

Sarah mailed her computer to Store B for repairs. Her bill was: Initial Repair Cost = $1,350 Sales Tax of 7 percent = $94.50 Tot

algol [13]

Answer:

28.89

Step-by-step explanation:

Total cost =$1444.50

shipping percent= 2%

So, there is written that Shipping = 2% of Total cost

Ship Cost= 2%×$1444.50

= $28.89

6 0

2 years ago

Read 2 more answers

A prticular type of tennis racket comes in a midsize versionand an oversize version. sixty percent of all customers at acertain

svetlana [45]

Answer:

a) P(x≥6)=0.633

b) P(4≤x≤8)=0.8989 (one standard deviation from the mean).

c) P(x≤7)=0.8328

Step-by-step explanation:

a) We can model this a binomial experiment. The probability of success p is the proportion of customers that prefer the oversize version (p=0.60).

The number of trials is n=10, as they select 10 randomly customers.

We have to calculate the probability that at least 6 out of 10 prefer the oversize version.

This can be calculated using the binomial expression:

$P(x\geq6)=\sum_{k=6}^{10}P(k)=P(6)+P(7)+P(8)+P(9)+P(10)\\\\\\P(x=6) = \binom{10}{6} p^{6}q^{4}=210*0.0467*0.0256=0.2508\\\\P(x=7) = \binom{10}{7} p^{7}q^{3}=120*0.028*0.064=0.215\\\\P(x=8) = \binom{10}{8} p^{8}q^{2}=45*0.0168*0.16=0.1209\\\\P(x=9) = \binom{10}{9} p^{9}q^{1}=10*0.0101*0.4=0.0403\\\\P(x=10) = \binom{10}{10} p^{10}q^{0}=1*0.006*1=0.006\\\\\\P(x\geq6)=0.2508+0.215+0.1209+0.0403+0.006=0.633$

b) We first have to calculate the standard deviation from the mean of the binomial distribution. This is expressed as:

$\sigma=\sqrt{np(1-p)}=\sqrt{10*0.6*0.4}=\sqrt{2.4}=1.55$

The mean of this distribution is:

$\mu=np=10*0.6=6$

As this is a discrete distribution, we have to use integer values for the random variable. We will approximate both values for the bound of the interval.

$LL=\mu-\sigma=6-1.55=4.45\approx4\\\\UL=\mu+\sigma=6+1.55=7.55\approx8$

The probability of having between 4 and 8 customers choosing the oversize version is:

$P(4\leq x\leq 8)=\sum_{k=4}^8P(k)=P(4)+P(5)+P(6)+P(7)+P(8)\\\\\\P(x=4) = \binom{10}{4} p^{4}q^{6}=210*0.1296*0.0041=0.1115\\\\P(x=5) = \binom{10}{5} p^{5}q^{5}=252*0.0778*0.0102=0.2007\\\\P(x=6) = \binom{10}{6} p^{6}q^{4}=210*0.0467*0.0256=0.2508\\\\P(x=7) = \binom{10}{7} p^{7}q^{3}=120*0.028*0.064=0.215\\\\P(x=8) = \binom{10}{8} p^{8}q^{2}=45*0.0168*0.16=0.1209\\\\\\P(4\leq x\leq 8)=0.1115+0.2007+0.2508+0.215+0.1209=0.8989$

c. The probability that all of the next ten customers who want this racket can get the version they want from current stock means that at most 7 customers pick the oversize version.

Then, we have to calculate P(x≤7). We will, for simplicity, calculate this probability substracting P(x>7) from 1.

$P(x\leq7)=1-\sum_{k=8}^{10}P(k)=1-(P(8)+P(9)+P(10))\\\\\\P(x=8) = \binom{10}{8} p^{8}q^{2}=45*0.0168*0.16=0.1209\\\\P(x=9) = \binom{10}{9} p^{9}q^{1}=10*0.0101*0.4=0.0403\\\\P(x=10) = \binom{10}{10} p^{10}q^{0}=1*0.006*1=0.006\\\\\\P(x\leq 7)=1-(0.1209+0.0403+0.006)=1-0.1672=0.8328$

7 0

2 years ago

In Drew's town the average price for a tutor is $15 per hour, and the standard deviation is $5.25 per hour. In Drew's town, what

alukav5142 [94]

Answer:

0.659 is the probability that a tutor charges between $10 and $20 per hour.

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = $15 per hour

Standard Deviation, σ = $5.25 per hour

We are given that the distribution of tutoring prices is a bell shaped distribution that is a normal distribution.

Formula:

$z_{score} = \displaystyle\frac{x-\mu}{\sigma}$

P( tutor charges between $10 and $20 per hour)

$P(10 \leq x \leq 20)\\\\ = P(\displaystyle\frac{10 - 15}{5.25} \leq z \leq \displaystyle\frac{20-15}{5.25})\\\\ = P(-0.9523 \leq z \leq 0.9523)\\\\= P(z \leq 0.9523) - P(z < -−0.9523)\\= 0.8295 - 0.1705= 0.659$

0.659 is the probability that a tutor charges between $10 and $20 per hour.

5 0

2 years ago

Logan wants to move to a new city. He gathered graphs of temperatures for two different cities. Which statements about the data

eduard

Answer:

we need the data to answer the question

3 0

2 years ago

1. Sarah has an average of 92.5 for her 3 science tests. What does she need to make on the 4th test to get a 94% average.

zheka24 [161]

1) set up a problem
you know you want to get an avg of 94 but how do you do avg in the first place. you add up the numbers then divde by the total number of numbers used lol

so $\frac{92.5+x}{2}=94$
92.5 is the avg number for the last 3 tests
"x" is the 4th test score which we want to find out
"2" is the total number of numbers being added together

so now lets get x to one side

92.5+ x=94*2 (multiply 2 to both sides)
92.5+x=188
x=188-92.5 (subtract 92.5 from both sides)
x= 95.5 this is the score she need to make to avg 94%

2) you can draw a tree diagram. for example Flower1 branches off into 3 diff greens and then each of those greens branch off into 2 for with or with babies breath.

or you can simple multiply 4*3*2. you can do this because all choices are included with no restriction

your total number of options is 24

4 0

2 years ago