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2 years ago

Decide which problems can be solved by using proportional reasoning. Select all that apply

Mathematics

2 answers:

Nookie1986 [14]2 years ago

8 0

Answer:

Step-by-step explanation:

4 doz for 7.25 = 12 doz for x

set up a proportion

4 12

------ = ------- cross multiply

7.25 x

4x = (7.25)(12)

4x = 87

x = 87/4

x = 21.75 <====

=========================

so we have 0.49 for the first oz.....and 0.22 for each additional oz....and there is 4 additional oz's because 5 - 1 = 4....so thats 0.49 + 4(0.22) = 0.49 + 0.88 = $ 1.37 for the cost of a 5 oz letter. <===

34kurt2 years ago

6 0

Answer:

Step-by-step explanation:

4 doz for 7.25 = 12 doz for x

set up a proportion

4 12

------ = ------- cross multiply

7.25 x

4x = (7.25)(12)

4x = 87

x = 87/4

x = 21.75

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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

Determine if the statement is true or false:

erma4kov [3.2K]

Answer:

Step-by-step explanation:

given are four statements and we have to find whether true or false.

.1 If two matrices are equivalent, then one can be transformed into the other with a sequence of elementary row operations.

True

2.Different sequences of row operations can lead to different echelon forms for the same matrix.

True in whatever way we do the reduced form would be equivalent matrices

3.Different sequences of row operations can lead to different reduced echelon forms for the same matrix.

False the resulting matrices would be equivalent.

4.If a linear system has four equations and seven variables, then it must have infinitely many solutions.

True, because variables are more than equations. So parametric solutions infinite only is possible

8 0

2 years ago

2.14x - 42.9 for x = 22.4 ? A. -18.36 B. 5.026 C. 47.939 D. 90.839

Fynjy0 [20]

Answer:

Step-by-step explanation:

Your answer would be B., because you would multiply

2.14 x 22.4 =

47.939

then you will subtract that by 42.9

47.939 - 42.9 =

5.026

7 0

2 years ago

A textbook store sold a combined total 402 of psychology and math textbooks in a week. The number of psychology textbooks sold w

uranmaximum [27]

Answer:

The number of textbooks of each type were sold is 134 math and 268 psychology books.

Step-by-step explanation:

Given:

Total number of math and psychology textbooks sold in a week is 402.

Now, let the number of math textbooks sold be $x$ .

And, the number of psychology textbooks be $2x$ .

According to question:

$x+2x=402$

$3x=402$

Dividing both sides by 3 we get:

$x=134$

So, total number of math textbooks were 134 .

And, total number of psychology textbooks were $2x=2\times 134$

$=268$ .

Therefore, the number of textbooks of each type were sold is 134 math and 268 psychology books.

4 0

2 years ago

Hailey paid \$13$13dollar sign, 13 for 1\dfrac3{7} \text{ kg}1 7 3 kg1, start fraction, 3, divided by, 7, end fraction, start

hichkok12 [17]

Answer:

1kg of salami cost $9.1

Step-by-step explanation:

Hailey paid $13 for 1 3/7 kg of sliced salami.

What was the cost per kilogram of salami?

Cost of 1 3/7 kg of sliced salami=$13

1 3/7 kg=10/7kg

Let x=1 kg of sliced salami

10/7 kg of x=$13

$13=10/7x

13=10/7*x

x=13 ÷ 10/7

=13×7/10

=91/10

=9.1

x=$9.1

Therefore, 1kg of salami cost $9.1

8 0

2 years ago