Is it True or false ?

A group of 100 students took a quiz. Their average score was 76 points. If the average score for the boys was 80 points and the

sveta [45]

Answer:

The number of girls participated in quiz is 40 .

Step-by-step explanation:

Given as :

Total number of students took quiz = 100

Average score of 100 students = 76 points

The Average score of boys = 80 points

The Average score of girls = 70 points

Let The number of boys participated in quiz = b

Let The number of girls participate in quiz = g

Now, According to question'

Total number of students took quiz = number of boys participated in quiz + number of girls participated in quiz

Or, b + g = 100 ........A

<u>Again</u>

∵ Average score of 100 students = 76 points

∴ Total score of 100 students = 76 × 100 = 7600

So, Average score of boys × number of boys participated + Average score of girls × number of girls participated = Total score of 100 students

Or, b × 80 + g × 70 = 7600

Or, 80 b + 70 g = 7600 .........B

Now, Solving equation A and B

(80 b + 70 g ) - 70 ×( b + g ) = 7600 - 70 × 100

I.e (80 b - 70 b) + (70 g - 70 g) = 7600 - 7000

Or, 10 b + 0 = 600

∴ b = $\dfrac{600}{10}$

i.e b = 60

So, The number of boys participated in quiz = b = 60

Put the value of b into eq A

∵ b + g = 100

So, g = 100 - b

Or, g = 100 - 60

i.e g = 40

So, The number of girls participated in quiz = g = 40

Hence, The number of girls participated in quiz is 40 . Answer

6 0

2 years ago

Kahleela starts the engine on her small private airplane. The engine drives a propeller with a radius of 8.5 feet and its center

algol13

Answer:

a=21.1

Step-by-step explanation:

You can use the given (incorrect) equation and fill in the value of t to find h:

h = 12.5 +9sin(750(3.5)) = 3.68 . . . . feet

__

Or, you can use the correct equation, or just your knowledge of revolutions:

h = 12.5 +9sin(750(2π·3.5)) = 12.5 . . . . feet

in 3.5 minutes at 750 revolutions per minute, the propeller makes 2625 full revolutions, so is back where it started — at 12.5 feet above the ground.

4 0

2 years ago

Read 2 more answers

A marketing firm is considering making up to three new hires. Given its specific needs, the management feels that there is a 50%

IRISSAK [1]

Answer:

a) 0.9

b) Mean = 1.58

Standard Deviation = 0.89

Step-by-step explanation:

We are given the following in the question:

A marketing firm is considering making up to three new hires.

Let X be the variable describing the number of hiring in the company.

Thus, x can take values 0,1 ,2 and 3.

$P(x\geq 2) = 50\%= 0.5\\P(x = 0) = 10\% = 0.1\\P(x = 3) = 18\% = 0.18$

a) P(firm will make at least one hire)

$P(x\geq 2) = P(x=2) + P(x=3)\\0.5 = P(x=2) + 0.18\\ P(x=2) = 0.32$

Also,

$P(x= 0) +P(x= 1) + P(x= 2) + P(x= 3) = 1\\ 0.1 + P(x= 1) + 0.32 + 0.18 = 1\\ P(x= 1) = 1- (0.1+0.32+0.18) = 0.4$

$\text{P(firm will make at least one hire)}\\= P(x\geq 1)\\=P(x=1) + P(x=2) + P(x=3)\\ = 0.4 + 0.32 + 0.18 = 0.9$

b) expected value and the standard deviation of the number of hires.

$E(X) = \displaystyle\sum x_iP(x_i)\\=0(0.1) + 1(0.4) + 2(0.32)+3(0.18) = 1.58$

$E(x^2) = \displaystyle\sum x_i^2P(x_i)\\=0(0.1) + 1(0.4) + 4(0.32) +9(0.18) = 3.3\\V(x) = E(x^2)-[E(x)]^2 = 3.3-(1.58)^2 = 0.80\\\text{Standard Deviation} = \sqrt{V(x)} = \sqrt{0.8036} = 0.89$

7 0

3 years ago

Solve the equation 4(2x – 1) + 8 = 4x + 24. Factor out the greatest common factor, then<br> solve.

DedPeter [7]

Answer:

5

Step-by-step explanation:

divide everything by 4

=(2x-1) +2 = x + 6

regroup

=2x = x + 5

x = 5

4 0

3 years ago

Read 2 more answers

The sum of two numbers is 180. one number is 5 times the other

stepan [7]

30 & 150. 150 is five times 30, and 150+30=180

8 0

2 years ago

Read 2 more answers