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Dafna11 [192]
3 years ago
9

A class of 28 students has 7 juniors and 21 seniors. The average (arithmetic mean) score of the juniors on a test was 73. The av

erage score of the seniors on the test was y. The average score of the entire class on the test was 85. Find y.
Mathematics
1 answer:
makkiz [27]3 years ago
6 0

Answer:

89

Step-by-step explanation:

Given that the class has 28 students has 7 juniors and 21 seniors

mean score of the juniors = 73

Therefore, total score of junior = 73 × 7

                                                   = 511

mean score of seniors = y

Total score of seniors = 21y

Total score of the class = 511 + 21y

Mean score of the class = 85

Total score of the class = 85 × 28

                                       = 2380

therefore,

511 + 21y = 2380

21y = 2380 -511

21y = 1869

y = 1869/21

y = 89

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Write the slope intercept form of the equation of the line through the given points. (5,-1) and (-5,2)
Lelu [443]

Answer:

y=-\frac{3}{10} x+\frac{1}{2} or -\frac{3}{10}

Step-by-step explanation:

first use the y2-y1/x2-x1 formula then use y=mx+b after

plug in 2 for y2 and -1 for y1

plug in -5 for x2 and 5 for x1

\frac{2-(-1)}{-5-5}=

2+1=3

-5-5=-10

-\frac{3}{10} is ur slope

_____________________

this is the y=mx+b formula *extra info ig*

i usually use the first point for this but u can use watever point u want

plug in 5 for x

plug in -1 for y

and plug -3/10 for m

-1=-3/10(5)+b

-3/10*5=-3/2

-1=-3/2+b

add -3/2 on both sides

-1+3/2=1/2

1/2=b and b is ur y-intercept

y=-3/10x+1/2

hope this helps

7 0
3 years ago
Find the measure of the angle with the red dot (NOT X.)<br> Picture Included. Thank you!
Afina-wow [57]

Step-by-step explanation:

I can't see picture very well but as I see first angle is

-4x+5 and second is -13x+39 ( if it isn't, correct me)

sum of this angles is 180° because they are inner angles

(-4x+5) + (-13x+39) = 180

-4x+5 -13x+39=180

-17x+44=180

-17x = 180-44

-17x= 136

x= -8

angle -4x+5 will be:

-4*-8 + 5= 32+5= 37°

3 0
3 years ago
a student has a savings account with $475 in it. she deposits $125 of her paycheck into the account every week.
soldier1979 [14.2K]

Answer:

350

Step-by-step explanation:

you just have to subtract ibthink

8 0
3 years ago
The cone had a radius of 4.5 inches and a height of 6 inches. What is the volume of this cone?
pochemuha

Answer:

125.8983

Step-by-step explanation:

Use the formula for volume of a cone: v= (1/3)(3.14)(radius squared)(height) so v = (1/3)(3.14)(20.25)(6) = 125.8983

4 0
3 years ago
a statistics professor finds that when he schedules an office hour at the 10:30a, time slot, an average of three students arrive
Veseljchak [2.6K]

Answer:

The probability that in a randomly selected office hour in the 10:30 am time slot exactly two students will arrive is 0.2241.

Step-by-step explanation:

Let <em>X</em> = number of students arriving at the 10:30 AM time slot.

The average number of students arriving at the 10:30 AM time slot is, <em>λ</em> = 3.

A random variable representing the occurrence of events in a fixed interval of time is known as Poisson random variables. For example, the number of customers visiting the bank in an hour or the number of typographical error is a book every 10 pages.

The random variable <em>X</em> is also a Poisson random variable because it represents the fixed number of students arriving at the 10:30 AM time slot.

The random variable <em>X</em> follows a Poisson distribution with parameter <em>λ</em> = 3.

The probability mass function of <em>X</em> is given by:

P(X=x)=\frac{e^{-\lambda}\lambda^{x}}{x!};\ x=0,1,2,3...,\ \lambda>0

Compute the probability of <em>X</em> = 2 as follows:

P(X=2)=\frac{e^{-3}3^{2}}{2!}=\frac{0.0498\times 9}{2}=0.2241

Thus, the probability that in a randomly selected office hour in the 10:30 am time slot exactly two students will arrive is 0.2241.

6 0
3 years ago
Read 2 more answers
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