All categories

3 years ago

Please help, will give brainliest to correct answer!

Mathematics

2 answers:

Tasya [4]3 years ago

8 0

If I can remember correctly... I've done this one before and had gotten it right. (It's been awhile.) I think it was the 3rd one. Hope it helps! Please forgive me if I remembered incorrectly. But I'm 100% sure that the 3rd one is the right one! hope it helps! :)

Papessa [141]3 years ago

3 0

The answer is 7/9.Hope it helps

You might be interested in

An office opens at 9am and closes at 5.30pm with a lunch break of 30minutes. What is the ratio of lunch break to the total perio

Alex777 [14]

Answer:

1:17

Step-by-step explanation:

Find out how long it it between 5.30pm and 9am. This is 8 hours 30 minutes or 510 minutes.

Now, arrange them in the ratio of Lunch Break to Total office time

30:510. This can be simplified to 1:17

Please check if the question is worded correctly, just in case. Because ratio questions are usually based on a part and the remaining parts of the same thing, and not part to whole.

Anyway. The answer given if for the question you have typed.

Hope this helps.

4 0

3 years ago

Read 2 more answers

If you are 600 m from a batter when you see him hit a ball, how long will you wait to hear the sound of the bat hitting the ball

Molodets [167]

Answer:

The speed of sound at 20°C is 343.42 m/s.

You have to wait 1.75 seconds to hear the sound of the bat hitting the ball

Step-by-step explanation:

Speed of Sound

The speed of sound is not constant with temperature. Generally speaking, the greater the temperature, the greater the speed of sound.

The approximate speed of sound in dry air at temperatures T near 0°C is calculated from:

$\displaystyle v_{\mathrm {s} }=(331.3+0.606\cdot T )~~~\mathrm {m/s}$

The air is at T=20°C, thus the speed of sound is:

$\displaystyle v_{\mathrm {s} }=(331.3+0.606\cdot 20 )~~~\mathrm {m/s}$

$v_{\mathrm {s} }=343.42\ m/s$

The speed of sound at 20°C is 343.42 m/s.

To calculate the time to hear the sound after the batter hits the ball, we use the formula of constant speed motion:

$\displaystyle v=\frac{d}{t}$

Where d is the distance and t is the time. Solving for t:

$\displaystyle t=\frac{d}{v}$

Substituting the values v=343.42 m/s and d=600 m:

$\displaystyle t=\frac{600}{343.42}$

t = 1.75 s

You have to wait 1.75 seconds to hear the sound of the bat hitting the ball

6 0

3 years ago

How to write this in slope-intercept form? 8x + 10y = 40

worty [1.4K]

Answer:y=-4/5x+4

Step-by-step explanation:

4 0

3 years ago

Read 2 more answers

Write a quadratic function to model the vertical motion for each situation, given h(t) equals negative 16t squared plus v0t+h0

Mashcka [7]

Answer:

hmax = 194 ft

The maximum height is 194 ft

Step-by-step explanation:

According to the given equation for the model of the vertical motion. The height at any point in time can be written as;

h(t) = -16t^2 + v0t + h0 .......1

Where;

h(t) = height at time t

t = time

v0 = initial velocity = 96 ft/s

h0 = initial height = 50 ft

To determine the maximum height we need to differentiate the equation 1 to find the time at which it reaches maximum height;

At the highest point/height h' = dh/dt = 0

h'(t) = -32t +v0 = 0

-32t + v0 = 0

t = v0/32

t = 96/32

t = 3 s

At t=3 it is at maximum height.

The maximum height can be derived from equation 1;

Substituting the values of t,v0,h0 into equation 1;

h(t) = -16t^2 + v0t + h0 .......1

hmax = -16(3)^2 + 96(3) + 50 = 194 ft

hmax = 194 ft

The maximum height is 194 ft

5 0

3 years ago

Amanda went to the store to purchase ink pens. She found three kinds of pens. The first cost $4 each; the price of the second ki

KonstantinChe [14]

Answer:

Amanda buy first kind of pen = 3

Amanda buy second kind of pen = 2

Amanda buy third kind of pen = 15

Step-by-step explanation:

Given - Amanda went to the store to purchase ink pens. She found three

kinds of pens. The first cost $4 each; the price of the second kind

was 4 for $1; and the cost for the third kind was 2 for $1. She bought

20 pens and she bought at least one of each kind. (It is possible to

buy only 1 of the pens that are "4 for $1" or "2 for $1".) The cost was

$20.

To find - When she got back to her office, Amanda decided to turn this into

a math problem for me. She asked: how many of each kind did I

buy?

Proof -

Let Amanda buy first kind of pen = x

second kind of pen = y

third kind of pen = z

As given,

She bought total pen = 20

⇒x + y + z = 20 ...............(1)

Now,

As given,

cost for first kind pen = $4 for 1 pen

As she bought x pens of first kind , so

Cost of x pens of first kind = $4x

Now,

The price of the second kind was 4 for $1

⇒Cost of second kind = $ $\frac{1}{4}$ for 1 pen

As she bought y pens of send kind , so

Cost of y pens of second kind = $ $\frac{1}{4}y$

Now,

The price of the third kind was 2 for $1

⇒Cost of third kind = $ $\frac{1}{2}$ for 1 pen

As she bought z pens of send kind , so

Cost of z pens of third kind = $ $\frac{1}{2}z$

Now,

As given, The cost was $20

⇒4x + $\frac{1}{4}y$ + $\frac{1}{2}z$ = 20

⇒16x + y + 2z = 80 .....................(2)

∴ we get 2 equations

x + y + z = 20 .....................(1)

16x + y + 2z = 80 .....................(2)

Now,

Subtract equation (1) from equation (2) , we get

16x + y + 2z - ( x+ y + z )= 80 - 20

⇒16x + y + 2z - x - y - z = 60

⇒15x + z = 60

⇒z = 60 - 15x

Now,

Put the value of z in equation (1) , we get

x + y + 60 - 15 x = 20

⇒ y - 14x = 20 - 60

⇒y - 14x = -40

⇒14x - y = 40

⇒y = 14x - 40

Now,

we get

z = 60 - 15x

y = 14x - 40

As given

she bought at least one of each kind

it means x > 1, y > 1, z > 1

Now,

If x = 1, then y = 14 - 40 = -26

Not possible

If x = 2 , then y = 14(2) - 40 = -12

Not possible

If x = 3, then y = 14(3) - 40 = 2 and z = 60 - 15(3) = 15

Possible.

If x = 4, then y = 14(4) - 40 = 16 and z = 60 - 15(4) = 0

Not Possible.

If x = 5, then y = 14(5) - 40 = 30 and z = 60 - 15(5) = -15

Not Possible.

∴ we get

x = 3, y = 2, z = 15

Amanda buy first kind of pen = x = 3

Amanda buy second kind of pen = y = 2

Amanda buy third kind of pen = z = 15

7 0

3 years ago