PLEASE HELP ASAP THANK YOU

In Psychology 101, the ratio of the number of girls to the number of boys is 3:1. After one girl drops the class and three more

aleksley [76]

Alright, lets get started.

Suppose the initial number of girls = x

Suppose the initial number of boys = y

The ratio of the number of girls to the number of boys is 3:1 (given in question)

x/y = 3/1

Cross multiply

x = 3 y ...............................equation (1)

one girl drops the class and three more boys sign up means new number of gilrs = x - 1

New number of boys = y + 3

the ratio of the number of girls to the number of boys becomes 5:2

(x-1) / (y+3) = 5/2

Cross multiplying

2 (x-1) = 5 (y+3)

2 x - 2 = 5 y + 15

Adding 2 in both sides

2 x - 2 + 2 = 5 y + 15 + 2

2 x = 5 y + 17 ..........................equation (2)

Putting value of x from equation 1 in equation 2

2 (3 y) = 5 y + 17

6 y = 5 y + 17

Subtracting 5 y in both sides

6 y - 5 y = 5 y + 17 - 5 y

y = 17

Putting the value of y in equation 1

x = 3 * 17 = 51

x = 51

After the changes, 1 girl drops : 51 - 1 = 50 new numbers of girls

After the changes, 3 more boys sign up : 17 + 3 = 20 new number of boys

So, total students in the class after changes : 50 + 20 = 70 students : Answer

Hope it will help :)

6 0

4 years ago

I need help with #6 please.

Juliette [100K]

9514 1404 393

Answer:

6. (A, B, C) ≈ (112.4°, 29.5°, 38.0°)

7. (a, b, C) ≈ (180.5, 238.5, 145°)

Step-by-step explanation:

My "work" is to make use of a triangle solver calculator. The results are attached. Triangle solvers are available for phone or tablet and on web sites. Many graphing calculators have triangle solvers built in.

__

We suppose you're to make use of the Law of Sines and the Law of Cosines, as applicable.

6. When 3 sides are given, the Law of Cosines can be used to find the angles. For example, angle A can be found from ...

A = arccos((b² +c² -a²)/(2bc))

A = arccos((8² +10² -15²)/(2·8·10)) = arccos(-61/160) = 112.4°

The other angles can be found by permuting the variables appropriately.

B = arccos((225 +100 -64)/(2·15·10) = arccos(261/300) ≈ 29.5°

The third angle can be found as the supplement to the other two.

C = 180° -112.411° -29.541° = 38.048° ≈ 38.0°

The angles (A, B, C) are about (112.4°, 29.5°, 38.0°).

__

7. When insufficient information is given for the Law of Cosines, the Law of Sines can be useful. It tells us side lengths are proportional to the sine of the opposite angle. With two angles, we can find the third, and with any side length, we can then find the other side lengths.

C = 180° -A -B = 145°

a = c(sin(A)/sin(C)) = 400·sin(15°)/sin(145°) ≈ 180.49

b = c(sin(B)/sin(C)) = 400·sin(20°)/sin(145°) ≈ 238.52

The measures (a, b, C) are about (180.5, 238.5, 145°).

7 0

3 years ago

Which describes a non-uniform probability model? A) heads or tails from a coin flip B) the sum result of rolling two dice C) sel

irga5000 [103]

Answer:

Option B.

Step-by-step explanation:

The non-uniform probability is when the event is not same in the occurring of event.

Option A is uniform because there will be equal chance of getting head or tail.

Option B is non-uniform because sum can be any number if we get(3,4) it will be 7 and if we have (2,3) then it will be 5.

Option C is uniform because we have equal number of red and green balls so, selecting a ball from both will be same.

Option D is uniform because chance of 1,2,,3,4,5 or 6 will be equal chance from rolling a die that is 1/6 in all cases.

Therefore, Option B is correct

7 0

3 years ago

Read 2 more answers

Which expressions are equivalent to -56z + 28.

NeX [460]

Answer:

B and C

Step-by-step explanation:

(-7)•8z = -56z

(-4)•(-7)=28

and

40•(-1.4)= -56z

40•0.7= 28

5 0

3 years ago

What is the angles mSRW?

Scilla [17]

Answer:

126°

Step-by-step explanation:

(2x +18)° = (3x)°

2x + 18 = 3x

18 = 3x - 2x

18 = x

therefore, (3x)° = (3*18)°= (54)°

$m\angle SRW + (3x)\degree = 180\degree \\m\angle SRW + 54\degree = 180\degree \\m\angle SRW = 180\degree - 54\degree \\\huge\red{\boxed{m\angle SRW = 126\degree}}$

5 0

3 years ago