Adv
  1. Frequency is the number of students having the same blood group. The frequency is represented in the table or the frequency distribution table: Blood Group Number of Students(Frequency) A 9 B 6 O 12 AB 3 Total 30 The most common Blood Group is the blood group with highest frequency: O The rarest BloRead more

    Frequency is the number of students having the same blood group. The frequency is represented in the table or the frequency distribution table:

    Blood Group Number of Students(Frequency)
    A 9
    B 6
    O 12
    AB 3
    Total 30

    The most common Blood Group is the blood group with highest frequency: O

    The rarest Blood Group is the blood group with lowest frequency: AB

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  2. Since the given data is very large, we construct a grouped frequency distribution table of class size 5. , class interval will be 0-5, 5-10, 10-15, 15-20 and so on. The data is represented in the grouped frequency distribution table as: In the given table the classes do not overlap. Also we find thaRead more

    Since the given data is very large, we construct a grouped frequency distribution table of class size 5. , class interval will be 0-5, 5-10, 10-15, 15-20 and so on. The data is represented in the grouped frequency distribution table as:

    Ncert solutions class 9 chapter 14-1

    In the given table the classes do not overlap. Also we find that, the houses of 36 out of 40 engineers are below 20 km of distance

     

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  3. Five examples from day-to-day life: Number of students in our class. Number of fans in our school. Electricity bills of our house for last two years. Election results obtained from television or newspapers. Literacy rate figures obtained from Educational Survey

    Five examples from day-to-day life:

    1. Number of students in our class.
    2. Number of fans in our school.
    3. Electricity bills of our house for last two years.
    4. Election results obtained from television or newspapers.
    5. Literacy rate figures obtained from Educational Survey
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  4. Primary data: when the information was collected by the investigator herself or himself with a definite objective in her or his mind, the data obtained is called primary data. Primary data; (i), (ii) and (iii) Secondary data; when the information was gathered from a source which already had the infoRead more

    Primary data: when the information was collected by the investigator herself or himself with a definite objective in her or his mind, the data obtained is called primary data.

    Primary data; (i), (ii) and (iii)

    Secondary data; when the information was gathered from a source which already had the information stored, the data obtained is called secondary data

    Secondary data; (iv) and (v)

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  5. (i) Radius of sphere, r = 7 cm Using, Volume of sphere = (4/3) πr3 = (4/3)×(22/7)×73 = 4312/3 Hence, volume of the sphere is 4312/3 cm3 (ii) Radius of sphere, r = 0.63 m Using, volume of sphere = (4/3) πr3 = (4/3)×(22/7)×0.633 = 1.0478 Hence, volume of the sphere is 1.05 m3 (approx).

    (i) Radius of sphere, r = 7 cm

    Using, Volume of sphere = (4/3) πr3

    = (4/3)×(22/7)×73

    = 4312/3

    Hence, volume of the sphere is 4312/3 cm3

    (ii) Radius of sphere, r = 0.63 m

    Using, volume of sphere = (4/3) πr3

    = (4/3)×(22/7)×0.633

    = 1.0478

    Hence, volume of the sphere is 1.05 m3 (approx).

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  6. (i) Diameter = 28 cm Radius, r = 28/2 cm = 14cm Volume of the solid spherical ball = (4/3) πr3 Volume of the ball = (4/3)×(22/7)×143 = 34496/3 Hence, volume of the ball is 34496/3 cm3 (ii) Diameter = 0.21 m Radius of the ball =0.21/2 m= 0.105 m Volume of the ball = (4/3 )πr3 Volume of the ball = (4/Read more

    (i) Diameter = 28 cm

    Radius, r = 28/2 cm = 14cm

    Volume of the solid spherical ball = (4/3) πr3

    Volume of the ball = (4/3)×(22/7)×143 = 34496/3

    Hence, volume of the ball is 34496/3 cm3

    (ii) Diameter = 0.21 m

    Radius of the ball =0.21/2 m= 0.105 m

    Volume of the ball = (4/3 )πr3

    Volume of the ball = (4/3)× (22/7)×0.1053 m3

    Hence, volume of the ball = 0.004851 m3

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  7. Given, Diameter of a metallic ball = 4.2 cm Radius(r) of the metallic ball, r = 4.2/2 cm = 2.1 cm Volume formula = 4/3 πr3 Volume of the metallic ball = (4/3)×(22/7)×2.1 cm3 Volume of the metallic ball = 38.808 cm3 Now, using relationship between, density, mass and volume, Density = Mass/Volume MassRead more

    Given,

    Diameter of a metallic ball = 4.2 cm

    Radius(r) of the metallic ball, r = 4.2/2 cm = 2.1 cm

    Volume formula = 4/3 πr3

    Volume of the metallic ball = (4/3)×(22/7)×2.1 cm3

    Volume of the metallic ball = 38.808 cm3

    Now, using relationship between, density, mass and volume,

    Density = Mass/Volume

    Mass = Density × volume

    = (8.9×38.808) g

    = 345.3912 g

    Mass of the ball is 345.39 g (approx).

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  8. Let the diameter of earth be “d”. Therefore, the radius of earth will be will be d/2 Diameter of moon will be d/4 and the radius of moon will be d/8 Find the volume of the moon : Volume of the moon = (4/3) πr3 = (4/3) π (d/8)3 = 4/3π(d3/512) Find the volume of the earth : Volume of the earth = (4/3)Read more

    Let the diameter of earth be “d”. Therefore, the radius of earth will be will be d/2

    Diameter of moon will be d/4 and the radius of moon will be d/8

    Find the volume of the moon :

    Volume of the moon = (4/3) πr3 = (4/3) π (d/8)3 = 4/3π(d3/512)

    Find the volume of the earth :

    Volume of the earth = (4/3) πr3= (4/3) π (d/2)3 = 4/3π(d3/8)

    Fraction of the volume of the earth is the volume of the moon

    Ncert solutions class 9 chapter 13-18

    Answer: Volume of moon is of the 1/64 volume of earth.

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  9. Diameter of hemispherical bowl = 10.5 cm Radius of hemispherical bowl, r = 10.5/2 cm = 5.25 cm Formula for volume of the hemispherical bowl = (2/3) πr3 Volume of the hemispherical bowl = (2/3)×(22/7)×5.253 = 303.1875 Volume of the hemispherical bowl is 303.1875 cm3 Capacity of the bowl = (303.1875)/Read more

    Diameter of hemispherical bowl = 10.5 cm

    Radius of hemispherical bowl, r = 10.5/2 cm = 5.25 cm

    Formula for volume of the hemispherical bowl = (2/3) πr3

    Volume of the hemispherical bowl = (2/3)×(22/7)×5.253 = 303.1875

    Volume of the hemispherical bowl is 303.1875 cm3

    Capacity of the bowl = (303.1875)/1000 L = 0.303 litres(approx.)

    Therefore, hemispherical bowl can hold 0.303 litres of milk.

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  10. Inner Radius of the tank, (r ) = 1m Outer Radius (R ) = 1.01m Volume of the iron used in the tank = (2/3) π(R3– r3) Put values, Volume of the iron used in the hemispherical tank = (2/3)×(22/7)×(1.013– 13) = 0.06348 So, volume of the iron used in the hemispherical tank is 0.06348 m3.

    Inner Radius of the tank, (r ) = 1m

    Outer Radius (R ) = 1.01m

    Volume of the iron used in the tank = (2/3) π(R3– r3)

    Put values,

    Volume of the iron used in the hemispherical tank = (2/3)×(22/7)×(1.013– 13) = 0.06348

    So, volume of the iron used in the hemispherical tank is 0.06348 m3.

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