All categories

2 years ago

What evidence do scientists have that erosion works slowly over long periods of time?

1 answer:

4 0

A noticeable evidence is that the Amazon was formed as a result of wearing away that has occurred over millions of years. Another good example is the Grand Canyon in the United States of America, it was formed as a result of erosion that occurred over 3 million years.

You might be interested in

In 2010, the population of a city was 161,000. From 2010 to 2015, the population grew by 8%. From 2015 to 2020, it fell by 6.7%.

solniwko [45]

Answer:

99%

Step-by-step explanation:

2010 population = 161,000

From 2010 to 2015, the population grew by 8%.

2010 to 2015 = 161,000 + (8% of 161,000)

= 161,000 + (0.08 * 161,000)

= 161,000 + 12,880

= 173,880

2010 to 2015 = 173,880

From 2015 to 2020, it fell by 6.7%

2015 to 2020 = 173,880 - (6.7% of 173,880)

= 173,880 - (0.067 * 173,880)

= 173,880 - 11,649.96

= 162,230.04

2015 to 2020 = 162,230.04

what percent did the city grow from 2010 to 2020.

= 161,000 / 162,230.04 × 100

= 0.9924179270374 × 100

= 99.241792703743

Approximately, 99% to the nearest whole number

4 0

2 years ago

Suppose the mean income of firms in the industry for a year is 95 million dollars with a standard deviation of 5 million dollars

GuDViN [60]

Answer:

Probability that a randomly selected firm will earn less than 100 million dollars is 0.8413.

Step-by-step explanation:

We are given that the mean income of firms in the industry for a year is 95 million dollars with a standard deviation of 5 million dollars. Also, incomes for the industry are distributed normally.

Let X = incomes for the industry

So, X ~ N( $\mu=95,\sigma^{2}=5^{2}$ )

Now, the z score probability distribution is given by;

Z = $\frac{X-\mu}{\sigma}$ ~ N(0,1)

where, $\mu$ = mean income of firms in the industry = 95 million dollars

$\sigma$ = standard deviation = 5 million dollars

So, probability that a randomly selected firm will earn less than 100 million dollars is given by = P(X < 100 million dollars)

P(X < 100) = P( $\frac{X-\mu}{\sigma}$ < $\frac{100-95}{5}$ ) = P(Z < 1) = 0.8413 {using z table]

Therefore, probability that a randomly selected firm will earn less than 100 million dollars is 0.8413.

5 0

2 years ago

A lake polluted by bacteria is treated with an antibacterial chemical. Aftertdays, thenumber N of bacteria per milliliter of wat

jeyben [28]

Answer:

N(1)=50 is a minimum

N(15)=4391.7 is a maximum

Step-by-step explanation:

Extrema values of functions

If the first and second derivative of a function f exists, then f'(a)=0 will produce values for a called critical points. If a is a critical point and f''(a) is negative, then x=a is a local maximum, if f''(a) is positive, then x=a is a local minimum.

We are given a function (corrected)

$N(t) = 20(t^2-lnt^2)+ 30$

$N(t) = 20(t^2-2lnt)+ 30$

(a)

First, we take its derivative

$N'(t) = 20(2t-\frac{2}{t})$

Solve N'(t)=0

$20(2t-\frac{2}{t})=0$

Simplifying

$2t^2-2=0$

Solving for t

$t=1\ ,t=-1$

Only t=1 belongs to the valid interval $1\leqslant t\leqslant 15$

Taking the second derivative

$N''(t) = 20(2+\frac{2}{t^2})$

Which is always positive, so t=1 is a minimum

(b)

$N(1)=20(1^2-2ln1)+ 30$

N(1)=50 is a minimum

(c) Since no local maximum can be found, we test for the endpoints. t=1 was already determined as a minimum, we take t=15

(d)

$N(15)=20(15^2-2ln15)+ 30$

N(15)=4391.7 is a maximum

7 0

2 years ago

Is it a proportional or not proportional

UNO [17]

Answer:

it is

Step-by-step explanation:

4 0

2 years ago

Read 2 more answers

A school replaced 20% of it computers with new ones . what the total number of computers in the school if 55 computers were repl

sladkih [1.3K]

The total is 275 because 100% divided by 20% is 5 and if 20%= 55 then that means that 55 goes into 100% 5 times so you multiply 55 by 5 to get 275. Hope I helped! Please rate me as the brainliest!

7 0

3 years ago