1. Let the lenght of the park = x Perimeter = 80 m Therefore, the breadth = 40 - x m [As Perimeter = 2 (Lenght + Breadth] According to question, Area = x (40 - x) = 400 ⇒ 40x - x² = 400 ⇒ x² - 40x + 400 = 0 ⇒ x² - 20x - 20x + 400 = 0 ⇒ x(x - 20) - 20(x - 20) = 0 ⇒ (x - 20) (x - 20) = 0 ⇒ (x - 12)² = 0Read more

    Let the lenght of the park = x
    Perimeter = 80 m
    Therefore, the breadth = 40 – x m [As Perimeter = 2 (Lenght + Breadth]
    According to question,
    Area = x (40 – x) = 400
    ⇒ 40x – x² = 400
    ⇒ x² – 40x + 400 = 0
    ⇒ x² – 20x – 20x + 400 = 0
    ⇒ x(x – 20) – 20(x – 20) = 0
    ⇒ (x – 20) (x – 20) = 0
    ⇒ (x – 12)² = 0 or (x – 13) = 0
    ⇒ (x – 20) = 0
    ⇒ x = 20
    Hence the lenght = 20 m and breadth of the park = 40 – 20 = 20 m.

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  2. Let, the time taken by large tap to fill the tank = x hours So, the time taken by smaller tap to fill the tank = x + 10 hours Therefore, in 1 hour, tank filled by larger tap = 1/x+10 According to question, 1/x + 1/x + 10 = 1/(9 (3/8)) ⇒ x + 10 + x/x(x + 10) = 8/75 ⇒ 75(2x + 10) = 8x(x + 10) ⇒ 150x +Read more

    Let, the time taken by large tap to fill the tank = x hours
    So, the time taken by smaller tap to fill the tank = x + 10 hours
    Therefore, in 1 hour,
    tank filled by larger tap = 1/x+10
    According to question,
    1/x + 1/x + 10 = 1/(9 (3/8))

    ⇒ x + 10 + x/x(x + 10) = 8/75
    ⇒ 75(2x + 10) = 8x(x + 10)
    ⇒ 150x +750 = 8x² + 80x
    ⇒ 8x² – 70x – 750 = 0
    ⇒ 4x² – 35x – 375 = 0
    ⇒ 4x² – 60x + 25x – 375 = 0
    ⇒ 4x(x – 15) + 25 (x – 15) = 0
    ⇒ (x – 15) (x + 25) = 0
    ⇒ (x – 15) = 0 or (x + 25) = 0
    Either x = 15 or x = – 25
    But, x ≠ – 25, as x is the time taken to fill the tank which can’t be negative. So, x
    Hence, the time taken by larger top to fill the tank = 15 hours
    and the time by smaller tap to fill the tank = 15 + 10 = 25 hours.

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  3. 2x² – 3x + 5 = 0 The given equations is of the form ax² + bx + c = 0, in which a = 2, b = - 3, c = 5. Therefore, D = b² - 4ac = (-3)² - 4 × 2 × 5 = 9 - 40 = - 31 < 0 Hence, there is no real roots for this quadratic equation.

    2x² – 3x + 5 = 0
    The given equations is of the form ax² + bx + c = 0, in which a = 2, b = – 3, c = 5.
    Therefore, D = b² – 4ac = (-3)² – 4 × 2 × 5 = 9 – 40 = – 31 < 0
    Hence, there is no real roots for this quadratic equation.

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  4. 2x² + kx + 3 = 0 For the quadratic equation 2x² + kx + 3 = 0 we have a = 2, b = k, c = 3. Therefore b² - 4ac = (k)² - 4 × 2 × 3 = k² - 24 For two equal roots, we have k² - 24 = 0 ⇒ k² = 24 ⇒ k = ±√24 ⇒ k = ±2√6.

    2x² + kx + 3 = 0
    For the quadratic equation 2x² + kx + 3 = 0 we have a = 2, b = k, c = 3.
    Therefore
    b² – 4ac = (k)² – 4 × 2 × 3 = k² – 24
    For two equal roots, we have k² – 24 = 0
    ⇒ k² = 24
    ⇒ k = ±√24
    ⇒ k = ±2√6.

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  5. Let, the breadth of mango grove = x m Therefore, the lenght = 2x m So, the area = x × 2x = 2x² According to question, 2x² = 800 ⇒ x² = 400 ⇒ x = ±20 Since, the breadth of the mango grove can't be negative, so the breadth = 20 m Hence, the lenght of the mango grove = 2 × 20 = 40 m.

    Let, the breadth of mango grove = x m
    Therefore, the lenght = 2x m
    So, the area = x × 2x = 2x²
    According to question, 2x² = 800
    ⇒ x² = 400
    ⇒ x = ±20
    Since, the breadth of the mango grove can’t be negative, so the breadth = 20 m
    Hence, the lenght of the mango grove = 2 × 20 = 40 m.

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