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3 years ago

3(2c-8) - 10c > 0 can some one explain how to solve this ?

Mathematics

1 answer:

Jet001 [13]3 years ago

8 0

Answer:

c < - 6

Step-by-step explanation:

Given

3(2c - 8) - 10c > 0 ← distribute and simplify left side

6c - 24 - 10c > 0

- 4c - 24 > 0 ( add 24 to both sides )

- 4c > 24

Divide both sides by - 4, reversing the inequality symbol as a consequence of dividing by a negative quantity.

c < - 6

You might be interested in

A rectangular field is to be enclosed by a fence and divided

Phantasy [73]

Answer:

80000 square meters

Step-by-step explanation:

perimeter + dividing fence = 800

let a = length

let b = width

let c = length of dividing fence

perimeter = 2*a + 2*b

let's say...

c is the same as the length

2a + 2b + c = 800

2a + 2b + a = 800

3a + 2b = 800

area = length*width

area = a*b

area / b = a

3*(area/b) + 2b = 800

3*(area/b) = 800 - 2b

area/b = (800 - 2b)

area = (800 - 2b)*b

To make the area large, we make the right hand side large.

800b - 2b^2

If you put in terms of x, y it looks like a downward opening parabola, so the max area is at the vertex. Half way between the roots.

y = -2x^2 + 800x

y = -x^2 + 400x

0 = x*(-x + 400)

roots are x= 0 and x = 400

vertex is at x, aka b = 200

area at b=200 is (800 - 400)*200 = 80000

and a is area/b... 80000/400 = 200

5 0

2 years ago

Roberto rowed 20 miles downstream in 2.5 hours. The trip back, however, took him 5 hours. Find the rate that Roberto rows in sti

almond37 [142]

Answer:

<em>Roberto's speed in still water is 6 miles/hour and the river speed is 2 miles/hour</em>

Step-by-step explanation:

<u>Relative Speed</u>

When a body is moving at a constant speed v, the distance traveled in a time t is:

$d=v.t$

When Roberto rows downstream, his speed in still water is added to the speed of the water, making it easier to travel the required distance.

When Roberto rows upstream, his speed in still water is affected by the speed of the water, both are subtracted and the required distance is covered in more time.

Let's call

x = Roberto's rowing speed in still water

y = Speed of the river current

The speed when rowing downstream is x+y, thus the distance traveled is

$d=(x+y).t_1$

Where t1=2.5 hours. Substituting values:

$20=(x+y)*2.5$

Rearranging, we find the downstream equation:

$2.5x+2.5y=20\qquad[1]$

The speed when rowing upstream is x-y, and the distance traveled is

$d=(x-y).t_2$

Where t2=5 hours. Substituting values:

$20=(x-y)*5$

Rearranging, we find the upstream equation:

$5x-5y=20\qquad[2]$

Multiplying [1] by 2:

$5x+5y=40$

Adding this equation to [2]:

$10x=60$

Solving:

$x=60/10=6$

Dividing [2] by 5:

$x-y=4$

Solving for y

$y=x-4=6-4=2$

Thus, Roberto's speed in still water is 6 miles/hour and the river speed is 2 miles/hour

3 0

3 years ago

Lin ride her bike 20 miles in 15 minutes. If she rode at constant speed what is the unit rate and how do you know ?

Varvara68 [4.7K]

$v=\frac{d}{t} \ \ \where: v=spped \ \ \ d=distane \ \ \ \ t=time\\
\\
\boxed{v=\frac{20 \ mi}{\frac{1}{4} \ h}=20*4=80 \ mi/h}$

6 0

3 years ago

4/3y=48<br><br>solve for y<br><br>simplify answer as much as posible

Helga [31]

$\frac{4}{3y} = 48 \\$

Inverse both sides

$\frac{3y}{4} = \frac{1}{48} \\$

Multiply both sides by 4

$4 \times \frac{3y}{4} = 4 \times \frac{1}{48} \\$

$3y = \frac{4}{48} \\$

$3y = \frac{4 \times 1}{4 \times 12} \\$

$3y = \frac{1}{12} \\$

Divide both sides by 3

$3y \div 3 = \frac{1}{12} \div 3 \\$

$y = \frac{1}{12} \times \frac{1}{3} \\$

$y = \frac{1}{36} \\$

_____________________________________________

$\frac{4}{3} y = 48 \\$

Multiply both sides by the 3

$3 \times \frac{4}{3} y = 3 \times 48 \\$

$4y = 3 \times 48$

Divide both sides by 4

$4y \div 4 = 3 \times 48 \div 4$

$y = \frac{48 \times 3}{4} \\$

$y = \frac{4 \times 12 \times 3}{4 \times 1} \\$

$y = 12 \times 3$

$y = 36$

6 0

2 years ago

Point A` is the imagen of point A under a rotation about the origin (0,0)

lys-0071 [83]

Answer:it’s 180 degrees

Step-by-step explanation:

4 0

2 years ago

3(2c-8) - 10c > 0 can some one explain how to solve this ?​

3(2c-8) - 10c > 0 can some one explain how to solve this ?