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3 years ago

A class of 25 students took a spelling test.

Mathematics

1 answer:

True [87]3 years ago

8 0

Answer:

90.6

Step-by-step explanation:

I think you have the first line incorrect. You show below that 10 students scored 90, so the first line is that 2 students scored 100, not 90. The line with the score of 90 is missing the number of students, but we can find it out. Call that number x for now.

Two students scored 100 each 2

x students scored 95 on each test x

ten students scored 90 on each test 10

three students score 80 on each test 3

and one student scored 70 <u> + 1 </u>

x + 16

There are x + 16 students accounted for. The total number of students is 25.

x + 16 = 25

x = 9

9 students scored 95 on each test.

Now add up all the points scored by all students.

Two students scored 100 each (2 * 90) 200

9 students scored 95 on each test (9 * 95) 855

ten students scored 90 on each test (10 * 90) 900

three students score 80 on each test (3 * 80) 240

and one student scored 70 (1 * 70) <u> + 70 </u>

Sum of all points: 2245

Now we find the average grade by dividing the sum of the points by the number of students.

average = sum/number = 2265/25 = 90.6

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Prime factorization of 50

prisoha [69]

The prime factorization of 50 is 2x5x5

4 0

4 years ago

Let u= <4,3>. Find the unit vector in the direction of u, and write your answer in component form.

aksik [14]

Take the vector u = <ux, uy> = <4, 3>.

Find the magnitude of u:

||u|| = sqrt[ (ux)^2 + (uy)^2]

||u|| = sqrt[ 4^2 + 3^2 ]

||u|| = sqrt[ 16 + 9 ]

||u|| = sqrt[ 25 ]

||u|| = 5

To find the unit vector in the direction of u, and also with the same sign, just divide each coordinate of u by ||u||. So the vector you are looking for is

u/||u||

u * (1/||u||)

= <4, 3> * (1/5)

= <4/5, 3/5>

and there it is.

Writing it in component form:

= (4/5) * i + (3/5) * j

I hope this helps. =)

3 0

3 years ago

If f(x)=-4x+1 what is f(-x/2)

guapka [62]

Answer:

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

Step-by-step explanation:

given f(x)=-4x+1................(1)

x= $\frac{-x}{2}$ put in equ (1)

f(x)=-4x+1

f( $\frac{-x}{2}$ ) =-4( $\frac{-x}{2}$ )+1

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

5 0

3 years ago

How do u do b??????????

horrorfan [7]

the assumption being that the first machine is the one on the left-hand-side and the second is the one on the right-hand-side.

the input goes to the 1st machine and the output of that goes to the 2nd machine.

if she uses and input of 6 on the 2nd one, the result will be 6² - 6 = 30, if we feed that to the 1st one the result will be √( 30 - 5) = √25 = 5, so, simply having the machines swap places will work to get a final output of 5.

clearly we can never get an output of -5 from a square root, however we can from the quadratic one, the 2nd machine/equation.

let's check something, we need a -5 on the 2nd, so

$\bf \underset{final~out put}{\stackrel{y}{-5}}=x^2-6\implies 1=x^2\implies \sqrt{1}=x\implies 1=x$

so if we use a "1" as the output on the first machine, we should be able to find out what input we need, let's do that.

$\bf \underset{first~out put}{\stackrel{y}{1}}=\sqrt{x-5}\implies 1^2=x-5\implies 1=x-5\implies 6=x$

so if we use an input of 6 on the first machine, we should be able to get a -5 as final output from the 2nd machine.

$\bf \stackrel{first~machine}{y=\sqrt{\boxed{6}-5}}\implies y=\sqrt{1}\implies y=1 \\\\\\ \stackrel{second~machine}{y = \boxed{1}^2-6}\implies y = 1-6\implies y = -5$

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3 years ago

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matrenka [14]

Answer:

YASS

Step-by-step explanation:

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