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3 years ago

Tomatoes cost $1.98 a pound.

Mathematics

1 answer:

Genrish500 [490]3 years ago

5 0

Answer:

Step-by-step explanation:

The way i estimate is i first look at the dollars and i mutiply that by 4 ($1x4)

you get 4 then we look at the cent which is $0.98 i would add in about 4 times and i would get to about $3 maybe. (This is mental math)

After that add 4 and 3 and you get 7

the estimated cost is about 7-8 dollars.

exact cost is-7.92

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What number added to 2 leaves 3 less than 3/5 of 10

inysia [295]

X + 2 = 3/5(10) - 3
x + 2 = 6 - 3
x + 2 = 3
x = 3 - 2
x = 1 <=== ur number

7 0

3 years ago

Read 2 more answers

A university found that 20% of its students withdraw without completing the introductory statistics course. Assume that 20 stude

EleoNora [17]

Answer:

a) $P(X \leq 2)= P(X=0)+P(X=1)+P(X=2)$

And we can use the probability mass function and we got:

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

And adding we got:

$P(X \leq 2)=0.0115+0.0576+0.1369 = 0.2061$

b) $P(X=4)=(20C4)(0.2)^4 (1-0.2)^{20-4}=0.2182$

c) $P(X>3) = 1-P(X \leq 3) = 1- [P(X=0)+P(X=1)+P(X=2)+P(X=3)]$

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

$P(X=3)=(20C3)(0.2)^3 (1-0.2)^{20-3}=0.2054$

And replacing we got:

$P(X>3) = 1-[0.0115+0.0576+0.1369+0.2054]= 1-0.4114= 0.5886$

d) $E(X) = 20*0.2= 4$

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Solution to the problem

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n=20, p=0.2)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

Part a

We want this probability:

$P(X \leq 2)= P(X=0)+P(X=1)+P(X=2)$

And we can use the probability mass function and we got:

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

And adding we got:

$P(X \leq 2)=0.0115+0.0576+0.1369 = 0.2061$

Part b

We want this probability:

$P(X=4)$

And using the probability mass function we got:

$P(X=4)=(20C4)(0.2)^4 (1-0.2)^{20-4}=0.2182$

Part c

We want this probability:

$P(X>3)$

We can use the complement rule and we got:

$P(X>3) = 1-P(X \leq 3) = 1- [P(X=0)+P(X=1)+P(X=2)+P(X=3)]$

$P(X=0)=(20C0)(0.2)^0 (1-0.2)^{20-0}=0.0115$

$P(X=1)=(20C1)(0.2)^1 (1-0.2)^{20-1}=0.0576$

$P(X=2)=(20C2)(0.2)^2 (1-0.2)^{20-2}=0.1369$

$P(X=3)=(20C3)(0.2)^3 (1-0.2)^{20-3}=0.2054$

And replacing we got:

$P(X>3) = 1-[0.0115+0.0576+0.1369+0.2054]= 1-0.4114= 0.5886$

Part d

The expected value is given by:

$E(X) = np$

And replacing we got:

$E(X) = 20*0.2= 4$

3 0

3 years ago

If a = 7 and b = 11, what is the measure of ∠B? (round to the nearest tenth of a degree) A) 32.5° B) 39.2° C) 50.5° D) 57.5°

Ilia_Sergeevich [38]

Answer:

D) 57.5°

Step-by-step explanation:

As the question is not complete. So, let's suppose it is a right angle triangle then, we can apply Pythagoras theorem to calculate the hypotenuse or the third side.

Pythagoras Theorem = $c^{2}$ = $a^{2} + b^{2}$

a = 7 and b = 11

$a^{2}$ = 49

$b^{2}$ = 121

Plugging in the values, we will get:

$c^{2}$ = 49 + 121

$c^{2}$ = 170

c = $\sqrt{170}$

To calculate the unknown angle B, we can use law of sine.

Law of sine = $\frac{a}{sinA}$ = $\frac{b}{sinB}$ = $\frac{c}{sinC}$

So,

$\frac{c}{sinC}$ = $\frac{b}{sinB}$

$\frac{\sqrt{170} }{sin90}$ = $\frac{11}{sinB}$

Sin90 = 1

sinB = $\frac{11}{\sqrt{170} }$

B = $sin^{-1}$ ( $\frac{11}{\sqrt{170} }$ )

B = 57.5°

8 0

3 years ago

If x is a positive integer and y is a negative integer than x + y is a rational number.

romanna [79]

Answer:

Yes

Step-by-step explanation:

An integer is a whole number so if x is positive and y is negative then the equation would just be x plus negative y. But x+-y is an odd equation so the simplified version is x-y so it is a rational number, since a rational number is a number that can be rewritten as a simple fraction.

5 0

4 years ago

5x+3-2x-2=4 solve for x

mrs_skeptik [129]

Answer:

x=1

Step-by-step explanation:

(5x+−2x)+(3+−2)=4

3x+1=4

3x=3

x=1

6 0

3 years ago

Read 2 more answers