China · Grade 7 · Practice Sheet 39

1. 1.

   A value changes from 191 to 59. 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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2. 2.

   Find the mean (average) of these numbers: 37, 98, 57, 94, 95.

   Formula:Arithmetic Mean

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

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3. 3.

   Find 2/8 of 96.

   Formula:Fraction of a Quantity

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

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4. 4.

   Find the perimeter of a rectangle measuring 20 m by 33 m.

   Formula:Perimeter of a Rectangle

   $P = 2(l + w)$

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5. 5.

   A value changes from 114 to 93. 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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6. 6.

   Find the perimeter of a rectangle measuring 31 m by 5 m.

   Formula:Perimeter of a Rectangle

   $P = 2(l + w)$

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7. 7.

   A rectangle is 32 cm long and 29 cm wide. Find its area.

   Formula:Area of a Rectangle

   $A = l \times w$

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8. 8.

   A car travels 86 km in 2 hours. Find its average speed.

   Formula:Speed

   $v = \dfrac{d}{t}$

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9. 9.

   One item costs ¥3.35. Find the total cost of 10 items.

   Formula:Total Cost

   $\text{total} = \text{price} \times \text{quantity}$

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10. 10.

    Convert 8.23 kilometres into metres.

    Formula:Metric Length Conversion

    $1\,\text{km} = 1000\,\text{m}$

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11. 11.

    Find 1/2 of 26.

    Formula:Fraction of a Quantity

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

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12. 12.

    A bag has 26 equally likely marbles, of which 22 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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13. 13.

    What is 12% of 140?

    Formula:Percentage of a Quantity

    $\text{result} = \dfrac{p}{100} \times N$

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14. 14.

    A circle has a radius of 14 cm. Find its area. (Use π ≈ 3.14159)

    Formula:Area of a Circle

    $A = \pi r^2$

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15. 15.

    Find the circumference of a circle whose radius is 10 m. (Use π ≈ 3.14159)

    Formula:Circumference of a Circle

    $C = 2\pi r$

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16. 16.

    Find the mean (average) of these numbers: 77, 83, 39, 51, 97, 88.

    Formula:Arithmetic Mean

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

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17. 17.

    ¥165 is shared in the ratio 2 : 3. Find each share.

    Formula:Dividing in a Ratio

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

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18. 18.

    One item costs ¥20.92. Find the total cost of 13 items.

    Formula:Total Cost

    $\text{total} = \text{price} \times \text{quantity}$

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19. 19.

    Find the area of a square with side length 26 cm.

    Formula:Area of a Square

    $A = s^2$

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20. 20.

    A right-angled triangle has legs of 8 cm and 4 cm. Find the length of the hypotenuse.

    Formula:Pythagorean Theorem

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

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