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m_a_m_a [10]
3 years ago
8

A textbook store sold a combined total of 217 biology and sociology textbooks in a week. The number of biology textbooks sold wa

s 59 more than the number of sociology textbooks sold. How many textbooks of each type were sold?
Mathematics
1 answer:
IrinaK [193]3 years ago
4 0

Answer:

79 sociology textbooks and 138 biology textbooks

Step-by-step explanation:

Create a system of equations, where b is the number of biology books and s is the number of sociology books:

b + s = 217

b = s + 59

Solve by substitution by substituting s + 59 for b into the first equation:

b + s = 217

s + 59 + s = 217

Add like terms and solve for s:

2s = 158

s = 79

So, there were 79 sociology books. To find the number of biology books, substitute 79 in for s into the equation b = s + 59

b = s + 59

b = 79 + 59

b = 138

So, 79 sociology textbooks and 138 biology textbooks were sold.

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Solve the following compound inequality: 3&lt;-2x-137.
yarga [219]

Answer:

Step-by-step explanation:

Here you go mate

PEDMAS

STEP 1

3<-2x-137  equation

STEP 2

3<-2x-137  simplify by reversing equation

-2x-137>3

STEP 3

-2x-137>3   simplify

-2x>140

step 4

-2x>140   look for a number that can divide the two numbers like 2

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3 years ago
A baker buys 10 pounds of peaches. She buys a total of 25 peaches. Given that 1 lb = 16 oz, what is the average weight, in ounce
creativ13 [48]

Answer:

the average weight  of one peach is 6.4 ounces

Step-by-step explanation:

10lb of peaches

16 ounces in a pound

10 x 16 = 160 ounces

divide 160 (ounces) by 25 (Peaches)  

= 6.4 ounces per peach

8 0
3 years ago
It is estimated that 75% of all young adults between the ages of 18-35 do not have a landline in their homes and only use a cell
Mademuasel [1]

Answer:

a) 75

b) 4.33

c) 0.75

d) 3.2 \times 10^{-13} probability that no one in a simple random sample of 100 young adults owns a landline

e) 6.2 \times 10^{-61} probability that everyone in a simple random sample of 100 young adults owns a landline.

f) Binomial, with n = 100, p = 0.75

g) 4.5 \times 10^{-8} probability that exactly half the young adults in a simple random sample of 100 do not own a landline.

Step-by-step explanation:

For each young adult, there are only two possible outcomes. Either they do not own a landline, or they do. The probability of an young adult not having a landline is independent of any other adult, which means that the binomial probability distribution is used to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

In which C_{n,x} is the number of different combinations of x objects from a set of n elements, given by the following formula.

C_{n,x} = \frac{n!}{x!(n-x)!}

And p is the probability of X happening.

The expected value of the binomial distribution is:

E(X) = np

The standard deviation of the binomial distribution is:

\sqrt{V(X)} = \sqrt{np(1-p)}

75% of all young adults between the ages of 18-35 do not have a landline in their homes and only use a cell phone at home.

This means that p = 0.75

(a) On average, how many young adults do not own a landline in a random sample of 100?

Sample of 100, so n = 100

E(X) = np = 100(0.75) = 75

(b) What is the standard deviation of probability of young adults who do not own a landline in a simple random sample of 100?

\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{100(0.75)(0.25)} = 4.33

(c) What is the proportion of young adults who do not own a landline?

The estimation, of 75% = 0.75.

(d) What is the probability that no one in a simple random sample of 100 young adults owns a landline?

This is P(X = 100), that is, all do not own. So

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

P(X = 100) = C_{100,100}.(0.75)^{100}.(0.25)^{0} = 3.2 \times 10^{-13}

3.2 \times 10^{-13} probability that no one in a simple random sample of 100 young adults owns a landline.

(e) What is the probability that everyone in a simple random sample of 100 young adults owns a landline?

This is P(X = 0), that is, all own. So

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

P(X = 0) = C_{100,0}.(0.75)^{0}.(0.25)^{100} = 6.2 \times 10^{-61}

6.2 \times 10^{-61} probability that everyone in a simple random sample of 100 young adults owns a landline.

(f) What is the distribution of the number of young adults in a sample of 100 who do not own a landline?

Binomial, with n = 100, p = 0.75

(g) What is the probability that exactly half the young adults in a simple random sample of 100 do not own a landline?

This is P(X = 50). So

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

P(X = 50) = C_{100,50}.(0.75)^{50}.(0.25)^{50} = 4.5 \times 10^{-8}

4.5 \times 10^{-8} probability that exactly half the young adults in a simple random sample of 100 do not own a landline.

8 0
3 years ago
Select all sets of lengths that would form a right triangle.
VARVARA [1.3K]

Answer:

theres no picture ill still answer if you put a picture or somthing of the triangle

Step-by-step explanation:

3 0
3 years ago
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