South Korea · Grade 7 · Practice Sheet 37

1. 1.

   Find the mean (average) of these numbers: 56, 85, 14, 31.

   Formula:Arithmetic Mean

   $\bar{x} = \dfrac{\sum x}{n}$

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2. 2.

   Find the circumference of a circle whose radius is 27 m. (Use π ≈ 3.14159)

   Formula:Circumference of a Circle

   $C = 2\pi r$

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3. 3.

   ₩3,200 is invested at 6% simple interest per year for 6 years. Find the interest earned.

   Formula:Simple Interest

   $I = \dfrac{P \times r \times t}{100}$

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4. 4.

   Find the circumference of a circle whose radius is 29 m. (Use π ≈ 3.14159)

   Formula:Circumference of a Circle

   $C = 2\pi r$

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5. 5.

   Find the area of a square with side length 9 cm.

   Formula:Area of a Square

   $A = s^2$

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6. 6.

   A bag has 8 equally likely marbles, of which 4 are red. Find the probability of drawing a red marble (to 3 d.p.).

   Formula:Simple Probability

   $P(E) = \dfrac{\text{favourable}}{\text{total}}$

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7. 7.

   Find the perimeter of a rectangle measuring 29 m by 6 m.

   Formula:Perimeter of a Rectangle

   $P = 2(l + w)$

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8. 8.

   ₩1,400 is invested at 10% simple interest per year for 2 years. Find the interest earned.

   Formula:Simple Interest

   $I = \dfrac{P \times r \times t}{100}$

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9. 9.

   Find 3/4 of 36.

   Formula:Fraction of a Quantity

   $\text{result} = \dfrac{a}{b} \times N$

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10. 10.

    Solve for x: 8x + 19 = 59.

    Formula:Solving a Linear Equation

    $x = \dfrac{c - b}{a}$

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11. 11.

    A value changes from 107 to 141. Find the percentage change (to 2 d.p.).

    Formula:Percentage Change

    $\%\,\text{change} = \dfrac{\text{new} - \text{old}}{\text{old}} \times 100$

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12. 12.

    ₩3,000 is invested at 6% simple interest per year for 4 years. Find the interest earned.

    Formula:Simple Interest

    $I = \dfrac{P \times r \times t}{100}$

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13. 13.

    ₩150 is shared in the ratio 1 : 5. Find each share.

    Formula:Dividing in a Ratio

    $\text{share} = \dfrac{\text{part}}{\text{total parts}} \times T$

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14. 14.

    Find 3/4 of 52.

    Formula:Fraction of a Quantity

    $\text{result} = \dfrac{a}{b} \times N$

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15. 15.

    ₩64 is shared in the ratio 4 : 4. Find each share.

    Formula:Dividing in a Ratio

    $\text{share} = \dfrac{\text{part}}{\text{total parts}} \times T$

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16. 16.

    A right-angled triangle has legs of 18 cm and 17 cm. Find the length of the hypotenuse.

    Formula:Pythagorean Theorem

    $c = \sqrt{a^2 + b^2}$

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17. 17.

    Find the perimeter of a rectangle measuring 16 m by 14 m.

    Formula:Perimeter of a Rectangle

    $P = 2(l + w)$

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18. 18.

    Solve for x: 6x + 12 = 42.

    Formula:Solving a Linear Equation

    $x = \dfrac{c - b}{a}$

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19. 19.

    A circle has a radius of 12 cm. Find its area. (Use π ≈ 3.14159)

    Formula:Area of a Circle

    $A = \pi r^2$

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20. 20.

    Find the perimeter of a rectangle measuring 32 m by 11 m.

    Formula:Perimeter of a Rectangle

    $P = 2(l + w)$

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