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lorasvet [3.4K]

3 years ago

9

In a class, 40% of the students are girls. Of the girls in the class, 25% play tennis. There are 40 students in the class. How m

any girls in this class, play tennis?
a- 10
b- 16
c- 4
d- 24

2 answers:

makkiz [27]3 years ago

8 0

Answer:

Let x=number of girls in the class

Then x+27 =total number of students in the class

So our equation to solve is :

40% of (x+27)=x or

0.40(x+27)=x get rid of parens

0.40x+10.8=x subtract 0.40x from each side

0.40x-0.40x+10.8=x-0.40x collect like terms

Step-by-step explanation:

ziro4ka [17]3 years ago

7 0

I think it’s B not sure tho

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The consumer price index is

nikklg [1K]

Answer:

A tool to measure the changes in the prices of weighted average market basket of goods and services purchased by consumers, usually households.

6 0

3 years ago

Please help! Thanks in advance.

alukav5142 [94]

In this problem, we need to plug in the given x values for $f(x)=0$ and find a and b.

When we plug in 1, we get: $2 \times {1}^{4} - 5 \times {1}^{3} - 14 \times {1}^{2} + a \times 1 + b = 0$

Simplify:
$2 - 5 - 14 + a + b = 0$
$- 17 + a + b = 0$
$a + b = 17$

We got our first statement about the values of the variables. If we find one more we can find those 2 variables.

We have another given root: 4.

Plug it in:
$2 \times {4}^{4} - 5 \times {4}^{3} - 14 \times {4}^{2} + a \times 4 + b = 0$
$512 - 320 - 224 + 4a + b = 0$
$- 32 + 4a + b = 0$
$4a + b = 32$

Now we have our second one. We can combine them:
$a + b = 17 \\ 4a + b = 32$

I use elimination method which is easier here.

Multiply the top equation by -1: $- a - b = - 17 \\ 4a + b = 32$

Add them up:
$3a = 15$

Simplify:
$a = 5$

Now we have a, we can plug in one of those equations to find b:
$5 + b = 17$
$b = 17 - 5$
$b = 12$

So, the answers are $a=5$ and $b=12$ .

6 0

3 years ago

A car is traveling at a speed of 30 meters per second. What is the car's speed in kilometers per hour? How many kilometers will

vitfil [10]

Answer:

216,000

Step-by-step explanation:

3 0

2 years ago

A type of green paint is made by mixing 2 cups of yellow with 3.5 cups of blue.

alexandr1967 [171]

Answer:

Use 1.75 cups of blue and 1 cup of yellow

Step-by-step explanation:

The given problem can be placed in the category of ratios and proportions. There is a ratio of color mixing which contains the proportion of two colors i.e blue and yellow. When we use 2 cups of yellow with 3.5 cups of yellow then we get green color so if we mix half of their amounts then we can get less or simply half amount of color too. Hence adding 1 cup of yellow and 1.75 cup of blue will give us small amount in result.

I hope this helps have a great day :)

8 0

2 years ago

Please explain how to find the answer

irina1246 [14]

Answer:

$\rm x=\frac{46}{3}$

$\rm y=-\frac{25}{24}$

Step-by-step explanation:

$\huge\begin{array} {|c|} \hline\left. \begin{cases} { \rm\frac{ 1 }{ 4 } x+ \frac{ 4 }{ 5 } y = 3 } \\ { \rm\frac{ 5 }{ 16 } x- \frac{ 1 }{ 5 } y=5 } \end{cases} \right. \\ \hline \end{array}$

$\\ \Large \overline{ \rm - \: Steps \: using \: substitution \: - }$

$\rm \frac{1}{4}x+\frac{4}{5}y=3$

$\rm \frac{1}{4}x=-\frac{4}{5}y+3$

$\rm x=4\left(-\frac{4}{5}y+3\right)$

$\rm x=-\frac{16}{5}y+12$

┈

$\rm \frac{5}{16}\left(-\frac{16}{5}y+12\right)-\frac{1}{5}y=5$

$\rm -y+\frac{15}{4}-\frac{1}{5}y=5$

$\rm -\frac{6}{5}y+\frac{15}{4}=5$

$\rm -\frac{6}{5}y=\frac{5}{4}$

$\bold{ y=-\frac{25}{24}}$

┈

$\rm x=-\frac{16}{5}\left(-\frac{25}{24}\right)+12$

$\rm x=\frac{10}{3}+12$

$\bold{ x=\frac{46}{3}}$

7 0

2 years ago

Read 2 more answers