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3 years ago

Jenna walks 4 miles in 1 hour at this rate how many miles can she walk in 3.5 hours

Mathematics

2 answers:

Nataliya [291]3 years ago

5 0

This is confusing123456789012346790

Leya [2.2K]3 years ago

3 0

Answer:

Step-by-step explanation:

well she walks 4 miles in an whole hour and she walks 3.5 hours so multiply 3.5 and 4

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chris is considering living at home for his freshman year of college in order to take some of his basic classes. according to th

Diano4ka-milaya [45]

Answer:

He would save 9,730$.

Step-by-step explanation:

At the 2y college, add the numbers and you'd get 6,400.

At the 4y college, you'd get 16,130.

You'd subtract the two to get 9,730.

3 0

3 years ago

Match the equations representing parabolas with their directrixes. y + 8 = 3(x + 2)2 y − 14 = -(x − 3)2 y + 7.5 = 2(x + 2.5)2 y

Shkiper50 [21]

Answer:

Part 1) $y+8=3(x+2)^{2}$ -----> $y=-8.08$

Part 2) $y-14=-(x-3)^{2}$ ----> $y=14.25$

Part 3) $y+7.5=2(x+2.5)^{2}$ ----> $y=-7.625$

Part 4) $y-17=-(x-3)^{2}$ -----> $y=17.25$

Part 5) $y+7=(x-4)^{2}$ ----> $y=-7.25$

Part 6) $y-6=-(x-1)^{2}$ ----> $y=6.25$

Step-by-step explanation:

we know that

The equation of a vertical parabola in vertex form is equal to

$y-k=\frac{1}{4p}(x-h)^{2}$

where

(h,k) is the vertex

The directrix is

$y=k-p$

case 1) we have

$y+8=3(x+2)^{2}$

the vertex is the point (-2,-8)

$\frac{1}{4p}=3$

$p=\frac{1}{12}$

The directrix is equal to

$y=-8-\frac{1}{12}=-8.08$

case 2) we have

$y-14=-(x-3)^{2}$

the vertex is the point (3,14)

$\frac{1}{4p}=-1$

$p=-\frac{1}{4}$

The directrix is equal to

$y=14+\frac{1}{4}=14.25$

case 3) we have

$y+7.5=2(x+2.5)^{2}$

the vertex is the point (-2.5,-7.5)

$\frac{1}{4p}=2$

$p=\frac{1}{8}$

The directrix is equal to

$y=-7.5-\frac{1}{8}=-7.625$

case 4) we have

$y-17=-(x-3)^{2}$

the vertex is the point (3,17)

$\frac{1}{4p}=-1$

$p=-\frac{1}{4}$

The directrix is equal to

$y=17+\frac{1}{4}=17.25$

case 5) we have

$y+7=(x-4)^{2}$

the vertex is the point (4,-7)

$\frac{1}{4p}=1$

$p=\frac{1}{4}$

The directrix is equal to

$y=-7-\frac{1}{4}=-7.25$

case 6) we have

$y-6=-(x-1)^{2}$

the vertex is the point (1,6)

$\frac{1}{4p}=-1$

$p=-\frac{1}{4}$

The directrix is equal to

$y=6+\frac{1}{4}=6.25$

5 0

3 years ago

. A field will be made in the shape of a rectangle with an area of 400 square meters. One side of the field is along a river and

Alex777 [14]

Answer:

The correct answer is $800.

Step-by-step explanation:

Let the length and width of the field be equal to l meters and b meters respectively and l > b.

Area of the field is given by l × b = 400 square meters.

The river is supposed to be along the longest side so that the price of fencing the other three sides is minimum. Thus the total perimeter of the fence is b+ b+ l = 2b+l.

Total cost for fencing the other sides of the field = $ 10 × (2b + l)

The wall is supposed to be perpendicular to the river and thus the length of the wall is b meters.

Total cost for the wall is $ 20 × b

Therefore, the total price for making the field is given by

C = 10 × (2b + l) + 20 × b

⇒ C = 40b + 10l

⇒ C = $\frac{16000}{l}$ + 10l

To minimize the cost we differentiate the cost with respect to l and equate it to zero.

$\frac{dC}{dl}$ = 0 = - $\frac{16000}{l^{2}}$ + 10

⇒ $l^{2}$ = 1600

⇒ l = 40 ; [ negative sign neglected as length cannot be negative ]

⇒ b = 10

The second order derivative of C is positive giving the minimum value of the cost.

Thus the minimum cost required to make the field is given by $800.

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3 years ago

Samples of rejuvenated mitochondria are mutated (defective) with probability 0.11. Find the probability you need to examine at l

joja [24]

Answer:

The probability that more than 6 samples are needed to have 2 mutations is P=0.866.

Step-by-step explanation:

This question can be analized with the binomial distribution.

We need to calculate the probability that more of 6 samples are needed to have 2 samples with mutations.

This is equal to the proability of taking 2 samples and getting one mutation or less.

Then we have a binomial distribution with n=6 and p=0.11:

$P(X\leq1)=P(0)+P(1)\\\\P(X\leq 1)=(1-p)^6+6p(1-p)^5\\\\P(X\leq 1)=0.89^6+6*0.11*0.89^5=0.497+0.369=0.866$

3 0

3 years ago

15x+18=-6x+2 i need help with this question

faust18 [17]

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3 years ago