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Mathematics

1 answer:

belka [17]3 years ago

3 0

Answer:

The answer to your questions is: 25 new teachers

Step-by-step explanation:

Data

# of students = 2000

ratio = 3:80 teachers to students

New teachers = ?

Process

I suggest to use rule of three to solve this problem

3 teachers ---------------- 80 students

x ---------------- 2000 students

x = (2000 x 3) / 80 = 75 teachers

Number of initial teachers = 75

The ratio change to 1:20

1 teacher ------------------- 20 students

x ------------------- 2000 students

x = (2000 x 1) / 20

x = 100 teachers

Number of new teachers = 100 - 75 = 25

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HELP ASAP , WILL GIVE MOST BRAINIEST

stepladder [879]

The pink is $y>2x +4$ and the purple is $x+y\leq 6$ . Have a great day!

4 0

3 years ago

Confirm that f and g are inverses by showing that f(g(x)) = x and g(f(x)) = x.

maks197457 [2]

F(g(x)) = [(-7x-8)/(x-1) - 8} / [(-7x - 8)/(x-1) + 7] =

[(-7x - 8 - 8(x-1)) / (x-1)] / [(-7x - 8 + 7(x-1)) / (x-1)] = (-15x) / (-15) = x.

g(f(x)) = [-7*(x-8)/(x+7) - 8] / [(x-8)/(x+7) - 1] =

[(-7x + 56 -8*(x+7)) / (x+7)] / [(x - 8 - (x + 7)) / (x+7)] = (-15x) / (-15) = x.

So since f(g(x)) = g(f(x)) = x we can conclude that f and g are inverses.

5 0

2 years ago

An hourglass consists of two sets of congruent composite figures on either end. Each composite figure is made up of a cone and a

belka [17]

Answer: third option 268.8

Explanation:

For this kind of proble it is very important that you attach the figure because it contains important information to understand the question.

I have attached the figure for better understanding.

1) The top portion (and the bottom is congruent but rotated 180°) of the hourglass is a figure equivalent to a cylinder on top and a cone on bottom.

So the total volume contained in the top portion is the volume of a cylinder + the volume of a cone.

This is how you calculate the volume of the top portion:

1) The height of the cylinder is 54 mm - 18 mm = 36 mm

2) The formula for the volume of a cylinder is V = π (radius)^2 * height

radius = 8 mm
height = 36 mm

=> V = π(8mm)^2 * 36 mm = 2304π (mm)^3

3) The formula for the volume of a cone is V = (1/3)π(radius)^2 * height

radius = 8 mm
height = 18 mm

V = (1/3)π(8mm)^2 * 18 mm = 384π (mm)^3

4) The total volume of the top portion is volumen of the cylindrical part + voume of the cone:

Total voluem = 2304π (mm)^3 + 384π (mm)^3 = 2688π (mm)^3

5) To find the number of seconds <span>it take until all of the sand has dripped to the bottom of the hourglass you have to divide the total volumen of sand by the rate:

time in seconds = total volume of sand / rate of dripping

time in seconds = [2688 π (mm)^3 ] / [10π (mm)^3 / s] = 268.8 s

That is the answer: 268.8 s
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