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2 years ago

The ratio of boys to girls in a class is 3:5. There are 40 students in the class. How many

Mathematics

1 answer:

Law Incorporation [45]2 years ago

5 0

Answer:

There are 25 girls in the class.

Step-by-step explanation:

Number of girls=5x

Number of boys=3x

Number of students in the class= 5x+3x=8x=40

So, x= 40/8=5

Number of girls= 5x=5*5=25

Therefore, there are 25 girls in the class.

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Erika worked 18 hours last week and 20 hours this week. If she earns $6 per hour, how much did she earn these two weeks?

Crank

Hi!

If she worked 18 hours last week and 20 hours this week, then she worked 38 hours in total, because 18 + 20 = 38.

If she earns $6 per hour, and she worked for 38 hours, then she got 38 sets of 6, which you can find the answer to by multiplying 38 and 6.

This is essentially 6 + 6 + 6 +...

38 * 6 = $228

So she earned $228 these two weeks.

Hope this helped!

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2 years ago

Read 2 more answers

anna wants to finish a 26.2 mile race in 5 hours. If she runs the first 3 hours of the race at a speed of 6 miles per hour, what

Oxana [17]

First off you need to multiply 6 by 3 for how many miles she went and then divide the leftover total by two (For the last two hours) to realize she needs to run 4.1 mph.

Hope this helped :)

3 0

2 years ago

Find the area of a quadrilateral ABCD in which AB = 3 cm, BC = 4 cm, CD = 4 cm, DA = 5 cm and AC = 5 cm.

melamori03 [73]

Answer:

$6+2\sqrt{21}\:\mathrm{cm^2}\approx 15.17\:\mathrm{cm^2}$

Step-by-step explanation:

The quadrilateral ABCD consists of two triangles. By adding the area of the two triangles, we get the area of the entire quadrilateral.

Vertices A, B, and C form a right triangle with legs $AB=3$ , $BC=4$ , and $AC=5$ . The two legs, 3 and 4, represent the triangle's height and base, respectively.

The area of a triangle with base $b$ and height $h$ is given by $A=\frac{1}{2}bh$ . Therefore, the area of this right triangle is:

$A=\frac{1}{2}\cdot 3\cdot 4=\frac{1}{2}\cdot 12=6\:\mathrm{cm^2}$

The other triangle is a bit trickier. Triangle $\triangle ADC$ is an isosceles triangles with sides 5, 5, and 4. To find its area, we can use Heron's Formula, given by:

$A=\sqrt{s(s-a)(s-b)(s-c)}$ , where $a$ , $b$ , and $c$ are three sides of the triangle and $s$ is the semi-perimeter ( $s=\frac{a+b+c}{2}$ ).

The semi-perimeter, $s$ , is:

$s=\frac{5+5+4}{2}=\frac{14}{2}=7$

Therefore, the area of the isosceles triangle is:

$A=\sqrt{7(7-5)(7-5)(7-4)},\\A=\sqrt{7\cdot 2\cdot 2\cdot 3},\\A=\sqrt{84}, \\A=2\sqrt{21}\:\mathrm{cm^2}$

Thus, the area of the quadrilateral is:

$6\:\mathrm{cm^2}+2\sqrt{21}\:\mathrm{cm^2}=\boxed{6+2\sqrt{21}\:\mathrm{cm^2}}$

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3 years ago

Marvel or DC? Which is better?

goldfiish [28.3K]

Answer: Abby- Marvel

Step-by-step explanation:

Just way better and deeper plotline in my personal opinion.

8 0

2 years ago

Read 2 more answers

In JKL, k=4.1 cm,j=3.8 cm and angle J=Q3^ Find all possible values of angle K , to the nearest inch of a degree .

spayn [35]

Answer:

74.0°

Step-by-step explanation:

In triangle JKL, k = 4.1 cm, j = 3.8 cm and ∠J=63°. Find all possible values of angle K, to the nearest 10th of a degree

Solution:

A triangle is a polygon with three sides and three angles. Types of triangles are right angled triangle, scalene triangle, equilateral triangle and isosceles triangle.

Given a triangle with angles A, B, C and the corresponding sides opposite to the angles as a, b, c. Sine rule states that for the triangle, the following holds:

$\frac{a}{sin(A)}=\frac{b}{sin(B)}=\frac{c}{sin(C)}$

In triangle JKL, k=4.1 cm, j=3.8 cm and angle J=63°.

Using sine rule, we can find ∠K:

$\frac{k}{sin(K)}=\frac{j}{sin(J)} \\\\\frac{4.1}{sin(K)}=\frac{3.8}{sin(63)} \\\\sin(K)=\frac{4.1*sin(63)}{3.8}\\\\sin(K)=0.9613\\\\K=sin^{-1} (0.9613)\\\\K=74.0^o \\$

6 0

2 years ago