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3 years ago

12

Chris read 20 pages of a novel each day for 9 days during summer break. How many total pages did Chris read during summer break?

A) 110 B) 180 C) 1100 D) 1800

1 answer:

Novay_Z [31]3 years ago

4 0

The answer to your question is,

B) 180. This is easily solvable with multiplication or a calculator.

-Mabel <3

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Allisa [31]

2miles=20km
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Runned 0.5 miles in total

3 0

2 years ago

Write an equation to solve each problem and then solve it. b In a 3-digit number, the hundreds digit is four more than the ones

Misha Larkins [42]

Answer:

digits are: 0, 4, 8. The required number is: 480.

Step-by-step explanation:

→ Let ones digits is 'x', then according to the condition the hundreds digit is 'x+4', and the tens digit is '2(x+4)'.

→ According to the condition the sum of the digits is: x+(x+4)+2(x+4)=12.

→ After evaluation this equation, x=0 - this is ones digit;

→ x+4=0+4=4 - this is hundreds digit;

→ 2(x+4)=2(0+4)=8 - this is ten digit.

3 0

3 years ago

What equation shows the relationship between the profit function, cost function and revenue function?

vlabodo [156]

Profit function - Cost function = Revenue function

6 0

3 years ago

Let X1,X2......X7 denote a random sample from a population having mean μ and variance σ. Consider the following estimators of μ:

Viefleur [7K]

Answer:

a) In order to check if an estimator is unbiased we need to check this condition:

$E(\theta) = \mu$

And we can find the expected value of each estimator like this:

$E(\theta_1 ) = \frac{1}{7} E(X_1 +X_2 +... +X_7) = \frac{1}{7} [E(X_1) +E(X_2) +....+E(X_7)]= \frac{1}{7} 7\mu= \mu$

So then we conclude that $\theta_1$ is unbiased.

For the second estimator we have this:

$E(\theta_2) = \frac{1}{2} [2E(X_1) -E(X_3) +E(X_5)]=\frac{1}{2} [2\mu -\mu +\mu] = \frac{1}{2} [2\mu]= \mu$

And then we conclude that $\theta_2$ is unbiaed too.

b) For this case first we need to find the variance of each estimator:

$Var(\theta_1) = \frac{1}{49} (Var(X_1) +...+Var(X_7))= \frac{1}{49} (7\sigma^2) = \frac{\sigma^2}{7}$

And for the second estimator we have this:

$Var(\theta_2) = \frac{1}{4} (4\sigma^2 -\sigma^2 +\sigma^2)= \frac{1}{4} (4\sigma^2)= \sigma^2$

And the relative efficiency is given by:

$RE= \frac{Var(\theta_1)}{Var(\theta_2)}=\frac{\frac{\sigma^2}{7}}{\sigma^2}= \frac{1}{7}$

Step-by-step explanation:

For this case we assume that we have a random sample given by: $X_1, X_2,....,X_7$ and each $X_i \sim N (\mu, \sigma)$

Part a

In order to check if an estimator is unbiased we need to check this condition:

$E(\theta) = \mu$

And we can find the expected value of each estimator like this:

$E(\theta_1 ) = \frac{1}{7} E(X_1 +X_2 +... +X_7) = \frac{1}{7} [E(X_1) +E(X_2) +....+E(X_7)]= \frac{1}{7} 7\mu= \mu$

So then we conclude that $\theta_1$ is unbiased.

For the second estimator we have this:

$E(\theta_2) = \frac{1}{2} [2E(X_1) -E(X_3) +E(X_5)]=\frac{1}{2} [2\mu -\mu +\mu] = \frac{1}{2} [2\mu]= \mu$

And then we conclude that $\theta_2$ is unbiaed too.

Part b

For this case first we need to find the variance of each estimator:

$Var(\theta_1) = \frac{1}{49} (Var(X_1) +...+Var(X_7))= \frac{1}{49} (7\sigma^2) = \frac{\sigma^2}{7}$

And for the second estimator we have this:

$Var(\theta_2) = \frac{1}{4} (4\sigma^2 -\sigma^2 +\sigma^2)= \frac{1}{4} (4\sigma^2)= \sigma^2$

And the relative efficiency is given by:

$RE= \frac{Var(\theta_1)}{Var(\theta_2)}=\frac{\frac{\sigma^2}{7}}{\sigma^2}= \frac{1}{7}$

5 0

3 years ago

You invest $24,000 at a simple interest rate of 12% for 9 years, and your

FinnZ [79.3K]

Answer:

The principal is $2400

Step-by-step explanation:

Given

$P = \$24000$

$t = 9$

$r =12\%$

$I = \$25920$

Required

The principal amount

The principal amount is the amount invested.

From the question, we understand that $24000 was invested.

Hence, the principal is $24000

8 0

3 years ago