1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
fomenos
3 years ago
12

Please help me I will mark brainliest! The ratio of the number of boys to the number of girls in a school is 3:4. One-third of t

he boys and three-eighths of the girls wear spectacles, If there are 612 pupils who do not wear spectacles, a)find the total number of the pupils in the school, and b) how many more girls than boys are there in the school
Mathematics
2 answers:
Alex17521 [72]3 years ago
7 0

Answer:

a) 952

b) 136

Step-by-step explanation:

<u>Ratio of b:g = 3:4, based on this we have:</u>

  • Number of boys = 3x
  • Number of girls = 4x
  • Total number of pupils = 3x+4x = 7x

<u>Number of spectacle wearers:</u>

  • 1/3*3x + 3/8*4x = x + 3/2x = 2.5x

<u>Number of those not wearing spectacles:</u>

  • 7x - 2.5x= 4.5x

<u>And this number equals to 612, then we can find the value of x:</u>

  • 4.5 x = 612
  • x= 612/4.5
  • x= 136

a) T<u>otal number of pupils:</u>

  • 7x = 7*136 = 952

b)<u> The difference in the number of boys and girls:</u>

  • 4x-3x= x = 136
fenix001 [56]3 years ago
7 0

Answer:

total number of students: 952

number of girls more than boys :136 more girls

Step-by-step explanation:

1/3 of boys +3/8 girls= spectacles

612 people do not wear spectacles

3:4= boys: girls

total number of students

3+4=7

boys + girls = total ratio

7= total ratio

1/3×3=1 3/8×4=3/2

1+3/2=5/2

7-5/2=9/2 9/2=612 students

If 9/2=612 Then 7=?

7= 7÷ 9/2×612

=952 people

Girls more than boys

if 7= 952

3= 3/7 × 952=408 boys

if 7 = 952

4= 4/7 ×952=544girls

Girls - boys

544- 408 = 136 girls

You might be interested in
Which of the following is a common characteristic of a binomial distribution?
Tanya [424]

Answer:

E. Each trial is independent

Step-by-step explanation:

I'm not completely sure why all binomial distribution trials are independent, but there are requirements for binomial distributions.

These requirements are:

- Each outcome is either a success (p) or a failure (Q)

- All trials are independent

- There are a fixed number of "n" trials

- The probability of success (p) is the same for each trial

I also just took the test and got this right.

6 0
2 years ago
An instructor in a college class recently gave an exam that was worth a total of 100 points. The instructor inadvertently made t
solniwko [45]

Answer:

B) Method 2 will increase the standard deviation of the students' scores.

Step-by-step explanation:

Given that an instructor in a college class recently gave an exam that was worth a total of 100 points.

The average score for his students was 43 and the standard deviation of the scores was 5 points.

And now he is considering two different strategies for rescaling the exam results of which:

Method 1 = Add 17 points to everyone's score.

Method 2 = Multiply everyone's score by 1.7 .

And we have to check what will be the impact of these methods on the standard deviation of the students' scores.

For this let us consider a simple example to understand this:

Firstly, Formula for calculating Standard Deviation =  \sqrt{\frac{\sum (X-Xbar)^{2}}{n-1}}

Suppose,

     X             X - Xbar       (X - Xbar)^{2}

     3              3 - 6 = -3         -3 * -3 = 9

     5              5 - 6 = -1          -1 * -1 = 1

     10            10 - 6 = 4          4 * 4 = 16

<em>Mean of above data, Xbar</em> = \frac{3+ 5+10}{3} = 6

<em>Standard Deviation of data </em>= \sqrt{\frac{26}{3-1} } = 3.6055

Now let us suppose that we multiply each value of above data with 2 so the new data will be:

     X                X - Xbar           (X - Xbar)^{2}

 3*2 = 6        6 - 12 = -6         -6 * -6 = 36

 5*2 = 10       10 - 12 = -2       -2 * -2 = 4

10*2 =20      20 - 12 = 8         8 * 8 = 64

<em>Mean of new data, Xbar </em>= \frac{6+ 10+20}{3} = 12

<em>Standard Deviation of new data</em> = \sqrt{\frac{104}{3-1} } = 7.2111

<em>Hence, we see that when we multiply any value to the data the standard deviation will increase and in other words it will multiplied by that value which value we multiplied with each data value i.e. when we multiply each data value with 2 the standard deviation also get multiplied by as </em>

  3.6055 * 2 = 7.2111

Therefore option B is correct that Method 2 will increase the standard deviation of the students' scores.

<em>And on the other hand Similarly by adding any constant to the data the Standard Deviation will remain same. Therefore Method 1 will have no impact on standard deviation of the students' scores.</em>

8 0
3 years ago
{fr33 p0intss 4 jay ifykyk kyky
expeople1 [14]

Answer:

yes

Step-by-step explanation:

8 0
2 years ago
Read 2 more answers
Find the slope of the line that passes through the following points a(4, -14) b(6, 18) ​
klemol [59]

Answer:

Slope=16

Step-by-step explanation:

4 0
2 years ago
a sprinkler that sprays water in a circular area can be adjusted to spray up to 30 feet. turning the radius-reduction screw on t
Zarrin [17]

Answer:

1590.4 square ft

Step-by-step explanation:

r=30 so you need to multiply that by 25% (30*.25=7.5)

30-7.5=22.5

A= pi(r)^2

A=pi*(22.5)^2

A=506.25pi

A=1590.43 or 1590.4 (to the nearest tenth)

4 0
3 years ago
Read 2 more answers
Other questions:
  • Find the surface area of the prism 2ft 1ft 3ft and 2.2ft
    12·1 answer
  • Interest is calculated by ____.
    11·2 answers
  • What is 3 divided by 3/5?
    9·1 answer
  • (20 POINTS AND BRAINLIEST ANSWER!!!) I need help with these two geometry 1 questions!!!
    12·1 answer
  • Which equation is correct regarding the measure of
    8·1 answer
  • Which of the following expressions is equal to -3x^2-12?
    11·1 answer
  • On average, Cody runs 4 miles in 38 minutes. How fast should he plan to run a 10-mile race if he maintains this pace?
    8·1 answer
  • Niles and Bob sailed at the same time for the same length of time. Niles' sailboat traveled 27 miles at a speed of 9 mph, while
    8·1 answer
  • Write an equation for the description.
    10·1 answer
  • Can someone help? If b/a=c/b=d/c=2/3, find a:b:c:d.
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!