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  1. Asked: July 10, 2024In:

    Find the value of (?) in √? + 28 = √1681

    Suptisree Biswas
    Suptisree Biswas Knowledge Contributor
    This answer was edited.

    Let the value ? be x. √x + 28 = √1681 => √x + 28 = 41 => √x = 41 – 28 => √x = 13 Now, squaring both sides – => (x^1/2)^2 = (13)^2 => x = 169 Answer: The value x is 169.

    Let the value ? be x.

    √x + 28 = √1681

    => √x + 28 = 41

    => √x = 41 – 28

    => √x = 13

    Now, squaring both sides –

    => (x^1/2)^2 = (13)^2

    => x = 169

    Answer: The value x is 169.

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  2. Asked: July 10, 2024In:

    A man purchased 147 stamps of 60-paise and 35, paise. The total amount he spent was ₹ 68.20. How many 35-paise stamps were purchased by him?

    Suptisree Biswas
    Suptisree Biswas Knowledge Contributor

    Number of 35-paise postal stamps = x Therefore, Number of 60-paise postal stamps = 147 - x Therefore, 35x + 60 (147 - x) = 6820 => 35x + 8820 - 60x = 6820 => 8820 - 25x = 6820 => 25x = 8820 - 6820 = 2000 => x = 2000 ÷ 25 = 80 Answer: 80 35-paise stamps were purchased by him.

    Number of 35-paise postal stamps = x
    Therefore, Number of 60-paise postal stamps = 147 – x
    Therefore, 35x + 60 (147 – x) = 6820
    => 35x + 8820 – 60x = 6820
    => 8820 – 25x = 6820
    => 25x = 8820 – 6820 = 2000
    => x = 2000 ÷ 25 = 80
    Answer: 80 35-paise stamps were purchased by him.

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  3. Asked: July 10, 2024In:

    If the simple interest for 6 years be equal to 30% of the principal, it will be equal to the principal after

    Suptisree Biswas
    Suptisree Biswas Knowledge Contributor

    Principal = Rs. x Interest = 30x/100 = Rs. 3x/10 Therefore, Rate = (Interest ×100)/(Principal × Time) = (3x × 100)/(10 × x × 6) = 5% per annum Case II, Interest = Rs. x Time = (x × 100)/(x × 5) = 20 years Answer: The simple interest will be equal to the principal after 20 years.

    Principal = Rs. x
    Interest = 30x/100 = Rs. 3x/10
    Therefore, Rate = (Interest ×100)/(Principal × Time)
    = (3x × 100)/(10 × x × 6) = 5% per annum
    Case II,
    Interest = Rs. x
    Time = (x × 100)/(x × 5) = 20 years
    Answer: The simple interest will be equal to the principal after 20 years.

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  4. Asked: July 10, 2024In:

    The selling price of an article is Rs. 3680 and profit percent age is 15%. The cost price of the article is

    Suptisree Biswas
    Suptisree Biswas Knowledge Contributor

    Cost price of item = 100/(100 + profit%) × Selling price = Rs. (100/115 × 3680) = Rs. 3200 Answer: The cost price of the article is Rs. 3200.

    Cost price of item
    = 100/(100 + profit%) × Selling price
    = Rs. (100/115 × 3680)
    = Rs. 3200
    Answer: The cost price of the article is Rs. 3200.

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  5. Asked: July 10, 2024In:

    In a class of 50 students, 15 do not participate in any games and the rest play at least one of two games Hockey or Kabaddi. 25 play Hockey and 20 play Kabaddi. Find the number of students who play both.

    Suptisree Biswas
    Suptisree Biswas Knowledge Contributor

    a + b + c = 50 - 15 = 35 a + b = 25 b + c = 20 Therefore, a + b + b + c = 45 => a + 2b + c = 45 Therefore, b = (a + 2b + c) - ( a + b +c) = 45 - 35 = 10 Answer: The number of students who play both is 10.

    a + b + c = 50 – 15 = 35
    a + b = 25
    b + c = 20
    Therefore, a + b + b + c = 45
    => a + 2b + c = 45
    Therefore, b = (a + 2b + c) – ( a + b +c)
    = 45 – 35
    = 10
    Answer: The number of students who play both is 10.

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  6. Asked: July 10, 2024In:

    Which of the following is not a rational number?

    Suptisree Biswas
    Suptisree Biswas Knowledge Contributor

    π is an irrational number. It's approximate value is 22/7.

    π is an irrational number. It’s approximate value is 22/7.

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  7. Asked: July 10, 2024In:

    If the surface area of a sphere is 2464 cm^2, then it's volume is

    Suptisree Biswas
    Suptisree Biswas Knowledge Contributor

    According to the question, 4πr^2 = 2464 => 4 × 22/7 × r^2 = 2464 => r^2 = (2464 × 7)/(4 × 22) => r = √196 => r = 14 cm Therefore, Volume of sphere = 4/3πr^3 = (4/3π × 14 × 14 × 14) cm^3 = 10976/3π cm^3 Answer: The volume of sphere is 10976/3π cm^3.

    According to the question, 4πr^2 = 2464
    => 4 × 22/7 × r^2 = 2464
    => r^2 = (2464 × 7)/(4 × 22)
    => r = √196
    => r = 14 cm
    Therefore, Volume of sphere = 4/3πr^3
    = (4/3π × 14 × 14 × 14) cm^3
    = 10976/3π cm^3
    Answer: The volume of sphere is 10976/3π cm^3.

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  8. Asked: July 10, 2024In:

    The perimeter of a semicircular plate of diameter 14 cm is

    Suptisree Biswas
    Suptisree Biswas Knowledge Contributor
    This answer was edited.

    Perimeter of semi-circular plate = πr + 2r = r (π + 2) =7 (22/7 + 2) = 7 × ((22 + 14)/7) = (7 × 36/7) cm = 36 cm Answer: The perimeter of semi-circular plate is 36 cm.

    Perimeter of semi-circular plate = πr + 2r

    = r (π + 2)

    =7 (22/7 + 2)

    = 7 × ((22 + 14)/7)

    = (7 × 36/7) cm

    = 36 cm
    Answer: The perimeter of semi-circular plate is 36 cm.

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  9. Asked: July 11, 2024In:

    Who is the Father of Mathematics?

    Suptisree Biswas
    Suptisree Biswas Knowledge Contributor

    Archimedes is the Father of Mathematics. He was a polymath who made significant contributions to a wide range of fields.

    Archimedes is the Father of Mathematics. He was a polymath who made significant contributions to a wide range of fields.

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  10. Asked: July 11, 2024In:

    Who invented zero (0)?

    Suptisree Biswas
    Suptisree Biswas Knowledge Contributor

    Aryabhata, a great astronomer of the classic age of India who invented zero (0).

    Aryabhata, a great astronomer of the classic age of India who invented zero (0).

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