All categories

3 years ago

There are 28 students in class the ratio of girls to boys is 3:4. How many girls

Mathematics

2 answers:

Gwar [14]3 years ago

8 0

Step-by-step explanation:

let the num be 3x & 4x

3x+4x=28

7x=28

x=28/7

x=4

now, num of girls=3x=3×4=12

& num of boys=4x=4×4=16

Elis [28]3 years ago

4 0

Answer: 12 girls

Step-by-step explanation: You first want to make this equation become a fraction with the number of girls on top and the total on bottom. This becomes 3/7. To make this over 28, multiply by 4 on the top and the bottom. This makes 12/28, making 12 girls the answer.

You might be interested in

It takes your garden hose 20 seconds to fill your 2-gallon watering can. How long will it take to fill

White raven [17]

Answer: a) 1791 seconds

b) 29701 seconds

Step-by-step explanation:

1 us gallon = 0.134 cubic foot

It takes your garden hose 20 seconds to fill your 2-gallon watering can. Converting 2 gallons to cubic foot, it becomes

2 × 0.134 = 0.268 cubic foot

a) The volume of inflatable pool measuring 3 feet wide, 8 feet long, and 1 foot deep.

Volume = 3 × 8 × 1 = 24 cubic feet

If 0.268 cubic foot = 20 seconds

24 cubic feet = (24 × 20)/0.268

= 1791 seconds

b) Volume of a cylinder is πr²h

Diameter = 13 feet

Radius = diameter/2 = 13/2 = 6.5

Volume of the circular pool is

3.14 × 6.5² × 3 = 397.995 cubic feet

If 0.268 cubic foot = 20 seconds

397.995 cubic feet = (397.995 × 20)/0.268

= 29701 seconds

5 0

4 years ago

A pasture is to be enclosed with 200 feet of fencing on three sides and a barn on the fourth side.

UNO [17]

Well lets have x be the side perpendicular to the barn. You will have two sides of length "x". Which means the side parallel to the barn has the length of (200 -2x)
So we know the area of the pasture is length * width or x * (200 - 2x)
This means we are seeking to maximize x * (200 - 2x).
This is actually a parabola with zeroes that are at x = 0 and x = 100 which means the vertex is at x = 50.
So when x = 50 > (200 - 2x) = 100
So that means the maximum area of the pasture is 50 * 100 = 5000 square feet.

6 0

3 years ago

5. Hailey would like to make a 5 lb coffee mixture that is 60% Sumatra coffee bean blend. She has several pounds of a mixture th

Genrish500 [490]

A] Given that the number of the unknowns are two, that is, x which represents the amount of the 20% blend and y which represents the amount of 80% blend, the system that models this situation is simultaneous equation.

b] The solution to the equation will be as follows;
Total amount of coffee to be made is:
x+y=5.........i
The percentage amount will be:
0.2x+0.8y=0.6*5
0.2x+0.8y=3.......ii
from eqn i
y=5-x.......iii
substituting iii in ii we get
0.2x+0.8(5-x)=3
0.2x+4-0.8x=3
solving for x we get:
0.2x-0.8x=3-4
-0.6x=-1
thus
x=1/0.6
x=5/3
y=5-x
y=5-5/3=10/3
thus the amount of x mixed is 5/3 lb and that of y is 10/3 lb

3 0

3 years ago

Read 2 more answers

Find the values of x and y.<br> (image below)

DanielleElmas [232]

Opposite angles have the same measures. This allows you to set and solve the following equations:

$\begin{cases} 26-6x = 20-8x \\ 5y = 9y-76 \end{cases}$

To solve both equations, let's move all the terms involving the variables on the left hand side, and all constant terms on the right hand side:

$\begin{cases} -6x+8x = 20-26 \\ 5y-9y = -76 \end{cases}$

Sum like terms:

$\begin{cases} 2x = -6 \\ -4y = -76 \end{cases}$

Divide the first equation by 2 and the second by -4:

$\begin{cases} x = -3 \\ y = 19 \end{cases}$

5 0

3 years ago

If h left-parenthesis x right-parenthesis equals f left-parenthesis x right-parenthesis times g left-parenthesis x right-parenth

alexgriva [62]

Given
h(x) = f(x)·g(x) = -x² -3x +4
Find
Possible equations for f(x) and g(x)

Solution
h(x) factors as -(x -4)(x +1)
There are an infinite number of possibilities for f(x) and g(x). Some of the simpler ones are ...
f(x) = 4 -x; g(x) = x +1
or
f(x) = -x -1; g(x) = x -4
or either of this with f and g swapped.

For some q(x), you can also have ...
f(x) = (4 -x)×q(x); g(x) = (x +1)/q(x)
again, possibly with f and g swapped

4 0

4 years ago