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ikadub [295]
3 years ago
5

There are 21 students in a class. The ratio of the number of boys to the number of girls is 4:3. How many girls are in the class

?
Mathematics
2 answers:
ZanzabumX [31]3 years ago
8 0

Answer:

Step-by-step explanation:

4:3 total is 7

8:6 total is 14

12:9 total is 21

So there are 9 girls.

k0ka [10]3 years ago
4 0

Answer: 9

Step-by-step explanation:

Given : There are 21 students in a class.

It is given that the ratio of the number of boys to the number of girls is 4:3.

Let 4x be the number of boys and 3x be the number of girls in class.

According to the question , we have

3x+4x=21\\\\\Rightarrow\ 7x=21\\\\\Rightarrow\ x=\dfrac{21}{7}=3

Now, the number of girls in class = 3x= 3(3)=9

Hence, there are 9 girls in class.

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The population of bacteria in an
aliina [53]

Answer:

Step-by-step explanation:

Future Amount = 25(1.8)^10 = 25* 357.047 = 8926.168 = 8926

6 0
3 years ago
I need help on these questions please! Quickly too
ale4655 [162]
By definition, a rational number is a precise number: or in other terms, we know its exact value. Irrational numbers are number that has endless digits on the right of the decimal points: in other terms, we can't know its exact value.

First question:
√2.5 = 1.58113.... It's endless, so irrational.
-√64 = -8 it's a whole number, so rational.
4√5 = 8.94427.... Endless, so irrational.
√14.4 = 3.7947... Endless so irrational.

So -√64 is the rational number.

Second:
7.885 is rational because has a defined number of digits after the decimal points.
π² = 9.8696.... Endless, so irrational.
√0.144 = 0.3794.... Endless, so irrational
√91 = 9.5393.... Endless, so irrational

So 7.885 is the rational number.

Third:
-7.8 bar: You can notice the line over the 8, this means that there's an infinite number of 8 after the decimal points. So it's 7.88888888888.... Endless, so irrational.
√25 = 5, whole number so rational
25.8125 Has a definite number of digits after the decimal point, so is rational.
√0.025 = 0.1581... Endless, so irrational.

So -7.8 bar and √0.025 are irrational.

Fourth:
π= 3.1415... Endless, so irrational.
1.425 has a definite number of digits after the decimal point, so rational.
√50 = 7.0710.... Endless, so irrational
√-4 Doesn't exist. Finding the square root of a negative number is mathematically impossible.

So 1.425 is the rational number.

Fifth:
√10 = 3.1622..... Endless, so irrational.
√100 = 10, a whole number so rational.
√1000 = 31.6227..... Endless, so irrational
√100000 = 316.2277...... Endless, so irrational.

√100 is the rational number.

Hope this helps!! :D And I hope you understood the lesson a bit more xD
5 0
4 years ago
Chris is older than Robb. When Chris and rob add their ages the some is 16. When they multiply their ages the product is 63. How
JulijaS [17]

Answer: the answer is given below

3 0
4 years ago
State if the two triangles are congruent.
sergiy2304 [10]

Answer:

The triangles are congruent  by HL

Step-by-step explanation:

The triangles are right triangles so we can use either HL ( hypotenuse leg) or LL (leg leg) if we know that two sides are congruent

We know one leg is equal to the other by the red line.  The hypotenuse is the same since it is the same line.

The triangles are congruent  by HL

5 0
3 years ago
If angle I is congruent to angle K find the perimeter of triangle JIK?
inessss [21]
The perimeter of a triangle is given by <em>the sum its three sides</em>, then according to the figure above we have that:

P=(7x-5)+(6x-5)+(9x-11) \\ \\ \therefore P=22x-21

Thus, our goal is to find the value of x and by finding it we will get the perimeter of the triangle. If ∠I = ∠K = β, then according to the Law of Sines we have:

\frac{9x-11}{sin \beta}= \frac{6x-5}{sin \beta} \\ \\ \therefore 9x-11=6x-5 \\ \therefore 3x=6 \therefore \boxed{x=2}

Lastly, the perimeter is:

P=22(2)-21 \rightarrow \boxed{P=23 \ units}

3 0
3 years ago
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