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3 years ago

13

Compare the average score of a student at the beginning of a month and at the end of that month, if at first, it increased by 40

%, then decreased by 25%

2 answers:

-BARSIC- [3]3 years ago

6 0

Answer: 5%

Step-by-step explanation:

Leno4ka [110]3 years ago

4 0

Answer:

122.5

Step-by-step explanation:

Let the student normal score be 100

In the beginning score increased by 40%

Hence score at the beginning =100+40 = 140%

Now before end score decreased by 25%

Decrease = 25% of 140 = 35

Hence score at the end of month = 140-35 = 105

Average score for the month

= Total of scores of end and beginning month /2

= $\frac{140+105}{2} \\=122.5$

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The caller times at a customer service center has an exponential distribution with an average of 22 seconds. Find the probabilit

jenyasd209 [6]

Answer:

The probability that a randomly selected call time will be less than 30 seconds is 0.7443.

Step-by-step explanation:

We are given that the caller times at a customer service center has an exponential distribution with an average of 22 seconds.

Let X = caller times at a customer service center

The probability distribution (pdf) of the exponential distribution is given by;

$f(x) = \lambda e^{-\lambda x} ; x > 0$

Here, $\lambda$ = exponential parameter

Now, the mean of the exponential distribution is given by;

Mean = $\frac{1}{\lambda}$

So, $22=\frac{1}{\lambda}$ ⇒ $\lambda=\frac{1}{22}$

SO, X ~ Exp( $\lambda=\frac{1}{22}$ )

To find the given probability we will use cumulative distribution function (cdf) of the exponential distribution, i.e;

$P(X\leq x) = 1 - e^{-\lambda x}$ ; x > 0

Now, the probability that a randomly selected call time will be less than 30 seconds is given by = P(X < 30 seconds)

P(X < 30) = $1 - e^{-\frac{1}{22} \times 30}$

= 1 - 0.2557

= 0.7443

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3 years ago

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2 years ago

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A 16 ounce box of cereal is priced at $3.68. Find the cost per ounce *

ZanzabumX [31]

Answer:

0.23$

Step-by-step explanation:

16 ounce box of cereal is priced at =3.68$

∴1 ounce box of cereal is priced at=(3.68/16)$

=0.23$

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3 years ago

Can someone Help with this question

inn [45]

Answer:

B 12

Step-by-step explanation:

manuel ate 1/3X
His brother ate 1/4X
leftover is 5
total is X

manuel+brother+leftover=X

x/3+x/4+5=x

7x+60/12=x

cross multiply

7x+60=12x

collect like terms

60=12x-7x

60=5x

divide both by 5

x=60/5

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3 years ago

17x-3y=4 2x-4y=1 the solution to the system of equations is

Burka [1]

ANSWER

$x=\frac{13}{62}$

and

$y= \frac{-9}{62}$ e have

EXPLANATION

$17x-3y=4---(1)$

$2x-4y=1$

Let us make y the subject and call it equation (2)

$2x=1+4y$

$x=\frac{1}{2}+2y--(2)$

We put equation (2) in to equation (1)

$17(\frac{1}{2}+2y)-3y=4$

$\frac{17}{2}+34y-3y=4$

$34y-3y=4- \frac{17}{2}$

Simplify to get,

$31y= \frac{8-17}{2}$

$31y= \frac{-9}{2}$

Divide both sides by 31,

$y= \frac{-9}{2} \div 31$

$y= \frac{-9}{2} \times \frac{1}{31}$

$y= \frac{-9}{62}$

We put this value in to equation (2) to get,

$x=\frac{1}{2}+2\times -\frac{9}{62}$

$x=\frac{1}{2} -\frac{18}{62}$

We collect LCM to obtain,

$x=\frac{31-18}{62}$

$x=\frac{13}{62}$

7 0

3 years ago