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
Anton [14]
3 years ago
6

Mr.Lee wants to survey 20 of the 210 students in seventh grade about the hours they slerp each night. He finds 2 of the 20 stude

nts surveyed sleep for 9 hours each night. About how many of the 210 seventh graders sleeo for 9 hours each night?​
Mathematics
1 answer:
allsm [11]3 years ago
6 0

21 students sleep for 9 hours each night

<em><u>Solution:</u></em>

Given that, Mr.Lee wants to survey 20 of the 210 students in seventh grade about the hours they sleep each night

He finds 2 of the 20 students surveyed sleep for 9 hours each night

Therefore, 2 out of 20 students sleep for 9 hours each night

Find out the percentage of 2 out of 20

\rightarrow \frac{2}{20} \times 100 = 10 \%

Thus 10 % of 210 students sleep for 9 hours each night

Find out 10 % of 210

\rightarrow 10\% \text{ of } 210\\\\\rightarrow 10 \% \times 210\\\\\rightarrow \frac{10}{100} \times 210\\\\\rightarrow 21

Thus 21 students sleep for 9 hours each night

You might be interested in
The accompanying data contains the depth​ (in kilometers) and​ magnitude, measured using the Richter​ Scale, of all earthquakes
Sunny_sXe [5.5K]

Answer:

Depth:

μ =20.2025 km

M = 15.625 km

Range = 47.15 km

σ ≈ 15.92 km

Q₁ = 5.7375 km

Q₃ =  34.6675 km

Magnitude:

μ = 2.08375

M = 1.465

Range, R = 5.17

σ = 1.801485 ≈ 1.8

Q₁ = 0.5625

Q₃ = 3.925

Step-by-step explanation:

The given data are;

Depth {}                                 Magnitude

0.76 {}                                    0.84

4.93 {}                                    0.47

8.16 {}                                     0.35

33.58 {}                                  1.32

21.2 {}                                     1.61

35.03 {}                                  4.57

10.05 {}                                   5.52

47.91 {}                                    1.99

For the Depth, we have;

The mean, μ = (0.76+4.93+8.16+33.58+21.2+35.03+10.05+47.91)/8 =20.2025 km

The median, M = The (n + 1)/2th term after arranging the term in increasing order as follows;

0.76, 4.93, 8.16, 10.05, 21.2, 33.58, 35.03, 47.91 , the median is therefore;

(8 + 1)/2th term or the 4.5th term which is 10.05 + (21.2 - 10.05)/2 = 15.625 km

The Range = The highest - The lowest value = 47.91 - 0.76 = 47.15 km

The Standard deviation of, σ, is given as follows;

\sigma =\sqrt{\dfrac{\sum \left (x_i-\mu  \right )^{2} }{N}}

Where;

x_i = The individual data point = (0.76, 4.93, 8.16, 10.05, 21.2, 33.58, 35.03, 47.91 )

N = The total number of data point = 8

Substituting, (using Microsoft Excel) we get;

\sigma =\sqrt{\dfrac{\sum \left (x_i-20.2025  \right )^{2} }{8}} \approx 15.92 \ km

Q₁ = The first quartile = The (n + 1)/4th =  term arranged in increasing order

Q₁ = The (8 + 1)/4th term = The 2.25th term = 4.93 + (8.16 - 4.93)×0.25) = 5.7375 km

Q₃ = The first quartile = The 3×(n + 1)/4th =  term arranged in increasing order

Q₃ = The 3×(8 + 1)/4th term = The 6.75th term = 33.58 + 3×(35.03 - 33.58)×0.25) = 34.6675 km

For the magnitude, we have, using the same formulas and procedures as above;

μ = 2.08375

M = 1.465

Range, R = 5.17

σ = 1.801485 ≈ 1.8

Q₁ = 0.5625

Q₃ = 3.925

4 0
3 years ago
Can someone answer this correctly for my sister please​
irina1246 [14]

Answer:

12) A ( 9, 11, 13, 15)

13) A ( o , a)

14) A  (b ∈ ( a, b, c, d, e, f))

15) C ( -364)

16) D (-1°C)

17) B (Negative)

18) C (26 feet)

19) B (7)

Step-by-step explanation:

12) All of these are odd numbers greater than 7

13) These are the only vowels in "MONDAY"

14) Point B cannot belong in a set that already has B

15) -9876 + 9512 = -364

16) 4 - 5 = -1

17) ex: -2 + (-2) = -4

18) -20 + 12 - 18 = -26

19) 3(5) + 4(-2) = 15 - 8 = 7

-Chetan K

8 0
2 years ago
The distribution of the amount of money spent by students on textbooks in a semester is approximately normal in shape with a mea
zheka24 [161]

Answer:

$301 - $397

Step-by-step explanation:

Using the Empirical rule

1) 68% of data falls within 1 standard deviation from the mean - that means between μ - σ and μ + σ .

2)95% of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ .

3)99.7% of data falls within 3 standard deviations from the mean - between μ - 3σ and μ + 3σ .

From the above question,

Mean = 349 , standard deviation = 24.

Confidence interval = 95%

Using 2)95% of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ .

μ – 2σ

= 349 - 2(24)

= 349 - 48

= 301

μ + 2σ

349 + 2(24)

= 349 + 48

= 397

Therefore, according to the standard deviation rule, approximately 95% of the students spent between $301 and $397 on textbooks in a semester.

8 0
3 years ago
A soccer coach bought some new uniforms and cleats for his team.
natka813 [3]
Uhhhh i cant answer this without details
7 0
3 years ago
LCM of 96,144,126 find it​
lidiya [134]

Answer:

2016

Step-by-step explanation:

To solve this problem, let us find the prime factors of the given numbers:

             96

        8   x    12

  2 x 2 x 2      2 x 2 x 3

              2⁵ x 3

             144

       12     x      12

  2 x 2 x 3       2 x 2 x 3

              2⁴  x 3²

                126

        2       x       63

      2                  7 x 9

     2                 3 x 3 x 7

            2 x 3² x 7

So, the lowest common multiple  =  2⁵ x 3² x 7  = 2016

6 0
3 years ago
Other questions:
  • Anne has a total of 3,500 golf balls at home. She loses some golf balls when she goes out on the driving range daily. The number
    11·2 answers
  • Keewan bike 6 miles in 30 minutes at this rate how long would it take him to bike 18 miles
    10·2 answers
  • 32. Mariah bought a shirt for $28.50 and a
    5·1 answer
  • Find the area of the shaded portion intersecting between the two circles.
    9·2 answers
  • Ron can make 12 benches in 6 days. At that<br> rate, how many benches can he make in<br> 30 days?
    14·1 answer
  • Will give brainliest to whoever answers first
    14·1 answer
  • Can you give the answers to these problems I let the pictures here (they are only two)
    15·1 answer
  • CAN SOMEONE HELP ME ON THIS QUESTION ASAP IT IS DUE IN 10 MORE MINUTES
    11·1 answer
  • If a=b+7 and b+7=9, then a=9
    8·1 answer
  • A trapezoid has base lengths of 12 centimeters and 13 centimeters. The other sides have lengths of 5 centimeters and 10 centimet
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!