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Ira Lisetskai [31]
3 years ago
7

A teacher has 3 hours to grade all the papers submitted by the 35 students in her class. She gets through the first 5 papers in

30 minutes. How much faster does she have to work to grade the remaining papers in the allotted time?
Mathematics
2 answers:
Andreyy893 years ago
8 0
So, she has 3hrs to grade all papers, for 35 students.. alrite.

the first 5, she does them in 30minutes.. what's the speed rate? well, 5/30 or 1/6

now, she has still 2 hours and a half, or 150 minutes, to do the remaining 30 papers... she has to work at a rate of 30/150 then... which is 1/5 simplified.

now if we take 1/6 as the 100%, what is 1/5 in percentage then?

\bf \begin{array}{ccllll}
rate&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
\frac{1}{6}&100\\\\
\frac{1}{5}&x
\end{array}\implies \cfrac{\frac{1}{6}}{\frac{1}{5}}=\cfrac{100}{x}\implies \cfrac{1}{6}\cdot \cfrac{5}{1}=\cfrac{100}{x}\implies \cfrac{5}{6}=\cfrac{100}{x}
\\\\\\
x=\cfrac{6\cdot 100}{5}\implies x=120

so 1/5 is 120% in relation to 1/6... meaning the rate of 1/5 she needs to move through, namely 1 paper every 5 minutes, is 20% faster than 1/6.
bonufazy [111]3 years ago
7 0
At first, she was grading papers at 10 papers per hour. To meet her time limit, she would have to begin grading them at 12 papers per hour, or 20% faster than her previous rate
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Figure out the costs of buying the two cars listed below by filling in the blanks in the table
a_sh-v [17]

Make/Model: 
Ford E-Series Wagon Van

<span>MSRP: </span>
$28,760

<span>Cost of options: </span>
$5,560

<span>Sales tax: </span>
$2230.80 (this is based on 6.5% interest)

<span>Total cost: </span>
$36550.80

<span>10% down payment: </span>
$3655.08

<span>Amount needed to borrow: </span>
$32895.72

<span>Monthly payment: </span>
$665.62

<span>Total interest paid: </span>
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Total payments:
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6 0
3 years ago
I dont get it plzzz help me
cricket20 [7]

Given Equation: \frac{1}{3}h-4(\frac{2}{3}h-3)=\frac{2}{3}h-6

Let us remove parenthesis first.

In order to remove parenthesis, we need to distribute -4 over parenthesis (2/3 h -3).

Distributing -4 over (2/3 h -3), we get,

-4*2/3 h - 4*-3 = -8/3 h + 12.

Substituting this value in original equation, we get

\frac{1}{3}h-\frac{8}{3}h+12 =\frac{2}{3}h-6

Now, in order to make the equation easy to solve, we always remove fractions. In order to remove fraction, we need to find the lowest common denominator of all terms(lcd).

The fraction terms has 3 in denominators, so we could multiply each and every term by 3 to remove 3's from denominators.

Multiplying each equation by 3, we get,

3*\frac{1}{3}h-3*\frac{8}{3}h+3*12 =3*\frac{2}{3}h-3*6

On simplfying this step, we get

1h -8h+36=2h-18

Combining like terms on left side, we get

-7h +36 = 2h -18.

Subtracting 36 from both sides, we get

-7h +36 -36= 2h -18-36.

-7h=2h-54

Subtracting 2h from both sides, we get

-7h-2h=2h-54-2h

-9h = -54

Dividing both sides by -9.

-9h/-9 = -54/-9

h = 6.

Therefore, final answer is h=6.


5 0
3 years ago
Please show your work and explain it.
Maru [420]

Answer:

f(x)=\dfrac{x+2}{2(x-2)}

Step-by-step explanation:

Remember when you divide fractions, you need to get the reciprocal of the divisor and multiply. So your first simplification would be:

\dfrac{x^2+4x+4}{x^2-6x+8}\div\dfrac{6x+12}{3x-12}\\\\=\dfrac{x^2+4x+4}{x^2-6x+8}\times\dfrac{3x-12}{6x+12}\\\\=\dfrac{(x^2+4x+4)(3x-12)}{(x^2-6x+8)(6x+12)}

Next we factor what we can so we can further simplify the rest of the equation:

=\dfrac{(x^2+4x+4)(3x-12)}{(x^2-6x+8)(6x+12)}\\\\=\dfrac{(x+2)(x+2)(3x-12)}{(x^2-6x+8)(6(x+2))}\\\\

We can now cancel out (x+2)

=\dfrac{(x+2)(3x-12)}{(x^2-6x+8)(6)}

Next we factor out even more:

=\dfrac{(x+2)(3)(x-4)}{(x-2)(x-4)(6)}

We cancel out x-4 and reduce the 3 and 6 into simpler terms:

=\dfrac{(x+2)(1)}{(x-2)(2)}

And we can now simplify it to:

=\dfrac{x+2}{2(x-2)}

6 0
3 years ago
The point P(9, 12) is on the terminal side of θ. Evaluate cos θ.
frutty [35]
<span>P(9,12): For all intents and purposes, the hypotenuse is "r", the opposite side is "y", and the adjacent side is "x".

x = 9 (from the P(9,12))
y = 12 (also from the point)

Using the Pythagorean Theorem, you find out that r = 15.

Therefore, since cos θ = x/r
cos θ = 9/15 or 3/5

Answer: 3/5</span>
7 0
3 years ago
A fair coin is tossed three times and the events A, B, and C are defined as follows: A: \{ At least one head is observed \} B: \
Yanka [14]

Answer:

a) P(A)=0.875

b) \text{P(A or B)}=0.875

c) \text{P((not A)  or B  or (not C))}=0.625

Step-by-step explanation:

Given : A fair coin is tossed three times and the events A, B, and C are defined as follows: A: At least one head is observed, B: At least two heads are observed, C: The number of heads observed is odd.

To find : The following probabilities by summing the probabilities of the appropriate sample points ?

Solution :

The sample space is

S={HHH,HHT,HTT,HTH,TTT,TTH,THH,THT}

n(S)=8

A: At least one head is observed

i.e. A={HHH,HHT,HTT,HTH,TTH,TTH,THH,THT}

n(A)=7

B: At least two heads are observed

i.e. B={HHH,HTT,TTH,THT}

n(B)=4

C: The number of heads observed is odd.

i.e. C={HHH,HTT,THT,TTH}

n(c)=4

a) Probability of A, P(A)

P(A)=\frac{n(A)}{n(S)}

P(A)=\frac{7}{8}

P(A)=0.875

b) P(A or B)

Using formula,

\text{P(A or B)}=P(A)+P(B)-\text{P(A and B)}

\text{P(A or B)}=\frac{n(A)}{n(S)}+\frac{n(B)}{n(S)}-\frac{\text{n(A and B)}}{n(S)}

\text{P(A or B)}=\frac{7}{8}+\frac{4}{8}-\frac{4}{8}

\text{P(A or B)}=\frac{7}{8}

\text{P(A or B)}=0.875

(c) P((not A)  or B  or (not C))

A={HHH,HHT,HTT,HTH,TTH,TTH,THH,THT}

not A = {TTT} = 1

B={HHH,HTT,TTH,THT}

C={HHH,HTT,THT,TTH}

not C = {HHT,HTH,THH,TTT} = 4

So, not A or B or not C = {HHH,HHT,HTH,THH,TTT}=5

\text{P((not A)  or B  or (not C))}=\frac{5}{8}

\text{P((not A)  or B  or (not C))}=0.625

4 0
3 years ago
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