Ask question

Ask question

All categories

Svetllana [295]

3 years ago

5

A group of students were asked if they carry a credit card. The responses are listed in

1 answer:

Stels [109]3 years ago

3 0

Part of the question is missing

You might be interested in

Help pls look at question, I'm confused so yeah.

lions [1.4K]

Answer

225 ml

Step-by-step explanation:

90 ml =2 parts

1 part=45

5 parts= 225

5 0

3 years ago

The radius of a cone is increasing at a constant rate of 7 meters per minute, and the volume is decreasing at a rate of 236 cubi

storchak [24]

Answer:

The rate of change of the height is 0.021 meters per minute

Step-by-step explanation:

From the formula

$V = \frac{1}{3}\pi r^{2}h$

Differentiate the equation with respect to time t, such that

$\frac{d}{dt} (V) = \frac{d}{dt} (\frac{1}{3}\pi r^{2}h)$

$\frac{dV}{dt} = \frac{1}{3}\pi \frac{d}{dt} (r^{2}h)$

To differentiate the product,

Let r² = u, so that

$\frac{dV}{dt} = \frac{1}{3}\pi \frac{d}{dt} (uh)$

Then, using product rule

$\frac{dV}{dt} = \frac{1}{3}\pi [u\frac{dh}{dt} + h\frac{du}{dt}]$

Since $u = r^{2}$

Then, $\frac{du}{dr} = 2r$

Using the Chain's rule

$\frac{du}{dt} = \frac{du}{dr} \times \frac{dr}{dt}$

∴ $\frac{dV}{dt} = \frac{1}{3}\pi [u\frac{dh}{dt} + h(\frac{du}{dr} \times \frac{dr}{dt})]$

Then,

$\frac{dV}{dt} = \frac{1}{3}\pi [r^{2} \frac{dh}{dt} + h(2r) \frac{dr}{dt}]$

Now,

From the question

$\frac{dr}{dt} = 7 m/min$

$\frac{dV}{dt} = 236 m^{3}/min$

At the instant when $r = 99 m$

and $V = 180 m^{3}$

We will determine the value of h, using

$V = \frac{1}{3}\pi r^{2}h$

$180 = \frac{1}{3}\pi (99)^{2}h$

$180 \times 3 = 9801\pi h$

$h =\frac{540}{9801\pi }$

$h =\frac{20}{363\pi }$

Now, Putting the parameters into the equation

$\frac{dV}{dt} = \frac{1}{3}\pi [r^{2} \frac{dh}{dt} + h(2r) \frac{dr}{dt}]$

$236 = \frac{1}{3}\pi [(99)^{2} \frac{dh}{dt} + (\frac{20}{363\pi }) (2(99)) (7)]$

$236 \times 3 = \pi [9801 \frac{dh}{dt} + (\frac{20}{363\pi }) 1386]$

$708 = 9801\pi \frac{dh}{dt} + \frac{27720}{363}$

$708 = 30790.75 \frac{dh}{dt} + 76.36$

$708 - 76.36 = 30790.75\frac{dh}{dt}$

$631.64 = 30790.75\frac{dh}{dt}$

$\frac{dh}{dt}= \frac{631.64}{30790.75}$

$\frac{dh}{dt} = 0.021 m/min$

Hence, the rate of change of the height is 0.021 meters per minute.

3 0

2 years ago

Answer asap 30 points!!!!!!!!!!!!!!!!!!!!!!!!!What is the lateral surface area of the cone?

Ludmilka [50]

Answer:

it would be a

3 0

2 years ago

0.580000 as a fraction

Paul [167]

Answer:

$\frac{58}{100}=\frac{29}{50}$

Step-by-step explanation:

Since this is mathematics, significant figures are not necessary. Thus, we can just take 0.58 and delete the 0s. Now, $0.58=\frac{58}{100}$ .

6 0

3 years ago

A man invest 5,200,part at 4% and the balance at 3%. If his total income for the two investments is $194,how much money did he i

Fed [463]

Let the amount invested at 4% be = x

Let the amount invested at 3% be = y

Given is:

$x+y=5200$ or $x=5200-y$ .... (1)

As, total income for the two investments is $194, so equation is:

$0.04x+0.03y=194$ ....(2)

Putting value of x from (1) in (2)

$0.04(5200-y)+0.03y=194$

$208-0.04y+0.03y=194$

$0.01y=14$

$y=1400$

And x=5200-y

$x=5200-1400=3800$

Hence, money invested at 4% is $3800 and money invested at 3% is $1400

6 0

2 years ago