1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
blsea [12.9K]
4 years ago
12

Kim is reading a book with 380 pages. she read 20 pages each day until she reached part 2 of the book. part 2 of the book is 160

pages long. she uses the equation 380−20d=160380-20d=160 to represent the number of days, d, it took her to read part 1. how many days did it take kim to read part 1 of the book?
Mathematics
1 answer:
Phoenix [80]4 years ago
8 0
If you would like to know how many days did it take Kim to read part 1 of the book, you can calculate this using the following steps:

d ... the number of days
380 pages - 20 pages * d = 160 pages
380 - 20 * d = 160
380 - 160 = 20 * d
220 = 20 * d
d = 220 / 20
d = 11 days

The correct result would be 11 days.
You might be interested in
There are 200 marbles in the bag, John picks 10 marbles out of
Airida [17]

Answer:

Step-by-step explanation:

favorable success: 6/10

marbles: 200

So

P=Favorable cases/total cases

P=6(20)/10(20)

P=120/200

8 0
3 years ago
Read 2 more answers
According to the WHO MONICA Project the mean blood pressure for people in China is 128 mmHg with a standard deviation of 23 mmHg
Alja [10]

Answer:

a) Let X the random variable that represent the blood pressure for people of a population, and for this case we know the distribution for X is given by:

X \sim N(128,23)  

Where \mu=128 and \sigma=23

b) P(X\geq 135)=P(\frac{X-\mu}{\sigma}\geq \frac{135-\mu}{\sigma})=P(Z\geq \frac{135-128}{23})=P(Z\geq 0.304)

And we can find this probability using the complement rule:

P(Z\geq 0.304)=1-P(Z

And in order to find this probabilities we can use tables for the normal standard distribution, excel or a calculator.  

P(Z\geq 0.304)=1-P(Z

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".  

Part a

Let X the random variable that represent the blood pressure for people of a population, and for this case we know the distribution for X is given by:

X \sim N(128,23)  

Where \mu=128 and \sigma=23

Part b

We are interested on this probability

P(X\geq 135)

And the best way to solve this problem is using the normal standard distribution and the z score given by:

z=\frac{x-\mu}{\sigma}

If we apply this formula to our probability we got this:

P(X\geq 135)=P(\frac{X-\mu}{\sigma}\geq \frac{135-\mu}{\sigma})=P(Z\geq \frac{135-128}{23})=P(Z\geq 0.304)

And we can find this probability using the complement rule:

P(Z\geq 0.304)=1-P(Z

And in order to find this probabilities we can use tables for the normal standard distribution, excel or a calculator.  

P(Z\geq 0.304)=1-P(Z

3 0
4 years ago
What is the factored form of the expression over the complex numbers?
ivolga24 [154]

It's the third answer. This is because since there is no middle term where both variables are combined, that would lead to the signs of the 2 factors to be different. However, that still leaves 2 answers, 3 and 2. If we were to square i, you would get -1. This is because √-1 is equal to i. i^2 would be -1. Since the sign in the unfactored expression is positive and not negative, that would mean that the i in the factoring turned it around. that leads us to believe that answer 3 is the correct answer.

6 0
3 years ago
Read 2 more answers
I need help with this
grandymaker [24]

Answer:

361

Step-by-step explanation:

discriminant = b² - 4ac

= (21)² - 4(1)(20)

= 441 - 80

= 361

5 0
2 years ago
5+[4×3(2+1)] what is the answer to it
kolezko [41]

Answer:

5+[4×3(2+1)] = 41

Step-by-step explanation:

Given that:

5+[4×3(2+1)]

  • Round bracket is solved first

=5+[4*3(3)]     as       (2+1=3)

  • Solving square bracket

=5+[4*9]        as         (3*3=9)

=5+[36]          as        (4*9=36)

=41                 as        (5+36=41)

I hope it will help you!

6 0
3 years ago
Other questions:
  • One boat travelling 15 mph goes 47 miles downstream in the same amount of time that another boat going 20 mph goes 40 miles upst
    13·1 answer
  • The period T (in seconds) of a pendulum is given by T=2\pi \sqrt((L)/(32)), where L stands for the length (in feet) of the pendu
    11·1 answer
  • 10 POINTS AND BRAINLIEST<br> ITS FOR MY SEMESTER TEST PLEASE HELP!!!<br> SEE PICTURE
    15·1 answer
  • Determine the value of a. <br> x^2 + ax + 6 = (x + 3)(x + 2)
    9·2 answers
  • Can you help please
    11·2 answers
  • 30 POINTS!!!!!Which of the following expressions has a value that is less than - 1/2 ? Select all that apply.
    10·1 answer
  • A hierarchy of quadrilaterals is shown. Name the figures that complete the hierarchy. Number the figures in your response to ind
    13·1 answer
  • The radius of a circle is 21 cm, what is the area?​
    6·1 answer
  • Identify the hypothesis of the statement If x + 4 = 5, then x = 1.
    12·1 answer
  • Please help me for 100 points and don't put in no fake answers -_-
    8·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!