All categories

4 years ago

If the ratio of boys to girls is 1:4 and there are 20 girls in your class, how many boys are there?

Mathematics

2 answers:

MAXImum [283]4 years ago

6 0

There are 5 boys in this class

Andre45 [30]4 years ago

4 0

There are 5 boys in the class

You might be interested in

Will give brainliest

algol [13]

Answer:

Step-by-step explanation:

-5x + 5

6 0

3 years ago

How do you solve 10+5(3x-4)=2x+7

Taya2010 [7]

Answer:

$x=1\dfrac{4}{13}$

Step-by-step explanation:

Given the equation

$10+5(3x-4)=2x+7$

Use distributive property:

$10+5\cdot 3x-5\cdot 4=2x+7\\ \\10+15x-20=2x+7$

Use commutative property to rewrite the equation:

$15x+10-20=2x+7$

$15x-10=2x+7$

Add 10 th both sides:

$15x-10+10=2x+7+10\\ \\15x=2x+17$

Subtract $2x:$

$15x-2x=2x+17-2x\\ \\13x=17$

Divide by 13:

$x=\dfrac{17}{13}=1\dfrac{4}{13}$

4 0

4 years ago

Factor the polynomial function over the complex numbers. f(x)=x^4-x^3-2x−4 Enter your answer in the box. f(x) = The answer is: (

Vladimir79 [104]

Answer:

Factors: $(x+i\sqrt2)(x-i\sqrt2)(x+1)(x-2)=0$

Step-by-step explanation:

We are given a polynomial:

$f(x)=x^4-x^3-2x-4$

We have to factor the given polynomial into its complex factors.

The factorization can be done as follows:

$f(x)=x^4-x^3-2x-4 = 0\\x^4-x^3-2x-4 = 0\\x^4-4-x^3-2x=0\\\text{Identity: }a^2-b^2 = (a+b)(a-b)\\(x^4-4)-(x^3+2x) = 0\\(x^2+2)(x^2-2)-x(x^2+2) = 0\\(x^2+2)(x^2-2-x) = 0\\(x^2+2)(x^2-x-2) = 0\\(x^2+2)(x^2-2x-+x-2) = 0\\(x^2+2)((x(x-2)+1(x-2))=0\\(x^2+2)(x+1)(x-2)=0\\\text{Identity: }a^2-b^2 = (a+b)(a-b)\\(x^2-(\sqrt{-2})^2)(x+1)(x-2)=0\\(x+i\sqrt2)(x-i\sqrt2)(x+1)(x-2)=0$

8 0

3 years ago

12.

g100num [7]

Answer:

Step-by-step explanation:

$tan^{-1} (\frac{\sqrt{3} }{3} )=x\\tan x=\frac{\sqrt{3} }{3} =tan (\frac{\pi}{6} )\\x=\frac{\pi}{6}$

7 0

3 years ago

Please explain how to do this, I'm using all my points A. 40 L B. 80 L C. 4 L D. 8L

exis [7]

Answer: choice A. 40 liters

====================================

Explanation:

x = number of liters of the 50% alcohol solution

If we have x liters of 50% alcohol, then we have 0.50*x liters of pure alcohol. This is added to 0.90*40 = 36 liters of pure alcohol (from the 90% solution).

So far we have 0.50*x + 36. This expression represents the total amount of pure alcohol. We want a 70% solution, so we want 70% of the total 40+x meaning 0.50*x + 36 is to be set equal to 0.70*(40+x) and we solve for x as shown below

0.50*x + 36 = 0.70*(40+x)

0.50*x + 36 = 0.70*(40)+0.70*(x)

0.50*x + 36 = 28+0.70*x

36 - 28 = 0.70*x - 0.50x

8 = 0.20x

0.20x = 8

x = 8/0.20

x = 40

So that is why the answer is choice A. 40 liters

6 0

3 years ago