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
Studentka2010 [4]
3 years ago
15

There are 420 books on a bookcase with 7 shelves. Each shelf has the same number of books. How many books are on 4 shelves? 28 6

0 120 240 ...
Mathematics
1 answer:
Ghella [55]3 years ago
3 0
If we have 420 books for every 7 shelves and are looking for how many books are on 4 shelves, we need to set up fractional proportions.

We have 7 shelves for every 420 books, so we will have our first fraction like this:
7/420.
We also have 4 shelves for every x books, so our second fraction will be 4/x.

Set these fractions up as an equation.
7/420 = 4/x

To solve for x, we need to cross multiply the numerators of one fraction with the denominators of the other fraction.
In other words, multiply the top number of one fraction by the bottom number of the other question.

It should look like this:
7(x)
420(4)

7(x) = 7x
420(4) = 1680

Set your products up as an equation.
7x = 1680

Now to solve for x, we need to simplify.
Currently, x is being multiplied by 7.
To get x alone, divide 7x by 7.
Remember, what you do to one side of an equation, you must do to the other, so divide 1680 by 7.

7x / 7 = x
1680 / 7 = 240

You are left with:
x = 240.

For every 4 shelves you have 240 books.

I hope this helps!

You might be interested in
Solve the equation for principal values of x. Express solutions in degrees.
Hitman42 [59]

Option C:

x = 90°

Solution:

Given equation:

\sin x=1+\cos ^{2} x

<u>To find the degree:</u>

\sin x=1+\cos ^{2} x

Subtract 1 + cos²x from both sides.

\sin x-1-\cos ^{2} x=0

Using the trigonometric identity:\cos ^{2}(x)=1-\sin ^{2}(x)

\sin x-1-\left(1-\sin ^{2}x\right)=0

\sin x-1-1+\sin ^{2}x=0

\sin x-2+\sin ^{2}x=0

\sin ^{2}x+\sin x-2=0

Let sin x = u

u^2+u-2=0

Factor the quadratic equation.

(u+2)(u-1)=0

u + 2 = 0,  u – 1 = 0

u = –2, u = 1

That is sin x = –2, sin x = 1

sin x can't be smaller than –1 for real solutions. So ignore sin x = –2.

sin x = 1

The value of sin is 1 for 90°.

x = 90°.

Option C is the correct answer.

3 0
2 years ago
Read 2 more answers
If f(x) = 2x²+2 and g(x) = x² - 1 ,find (f- g)(x).
mestny [16]

Step-by-step explanation:

(F-g) (X)

= f(x) - g(x)

(2x² + 2 )-(x²-1) =

3x²+3

4 0
3 years ago
Take 56 and divide it by 4
Hunter-Best [27]
The answer will be 9 ok
3 0
3 years ago
Read 2 more answers
4 friends went to the movies and each ordered a container of popcorn.They spent $24 on popcorn.How much did each container of po
alexandr402 [8]

Answer: $6

Step-by-step explanation:

24/4 = 6

5 0
3 years ago
Read 2 more answers
Subvert
nadezda [96]
So...lets first think about what the word means to actually determine its synonyms. 

Subvert :- To overthrow, or take down 

Since this refers to an action that is upsetting, that would best fit the synonym.

Answer; To upset  

7 0
2 years ago
Other questions:
  • During a renovation project for the train station a parking lot for commuter train passengers is being enlarged. The original lo
    10·2 answers
  • 87.5% of what number is 49?
    15·1 answer
  • X2-3x+2=0 solve this
    8·1 answer
  • Find the x and y intercepts of the line. (i dont remember how to do this. ​
    5·1 answer
  • E. To remove a zero pair, drag a box around the pair and click Remove. Remove all of the zero pairs.
    7·1 answer
  • You work 20 hours a week at a store in our $8.50 per hour. At another job you earn $8.00 per hour and can work as many hours as
    15·2 answers
  • What is the nth term rule of the linear sequence below?<br> 13, 7, 1, -5, -11,...
    11·2 answers
  • Como resuelvo esta inecuació 2x + 8 ≥ 20?
    5·1 answer
  • 8 more than s stripes
    15·1 answer
  • ILL MARK BRAINIEST IF YOU DO THIS RIGHT!!! DO 9 AND 10!!!
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!