Chile · Grado 8 · Practice Sheet 7

1. 1.

   Find the mean (average) of these numbers: 30, 18, 61, 35, 54.

   Formula:Arithmetic Mean

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

   View formula →
2. 2.

   A bag has 24 equally likely marbles, of which 5 are red. Find the probability of drawing a red marble (to 3 d.p.).

   Formula:Simple Probability

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

   View formula →
3. 3.

   A value changes from 103 to 128. Find the percentage change (to 2 d.p.).

   Formula:Percentage Change

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

   View formula →
4. 4.

   Find the mean (average) of these numbers: 17, 37, 83, 88, 89, 32.

   Formula:Arithmetic Mean

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

   View formula →
5. 5.

   A right-angled triangle has legs of 14 cm and 12 cm. Find the length of the hypotenuse.

   Formula:Pythagorean Theorem

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

   View formula →
6. 6.

   Find the circumference of a circle whose radius is 21 m. (Use π ≈ 3.14159)

   Formula:Circumference of a Circle

   $C = 2\pi r$

   View formula →
7. 7.

   Solve for x: 3x + 6 = 36.

   Formula:Solving a Linear Equation

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

   View formula →
8. 8.

   A cylinder has radius 2 cm and height 17 cm. Find its volume. (π ≈ 3.14159)

   Formula:Volume of a Cylinder

   $V = \pi r^2 h$

   View formula →
9. 9.

   $136 is shared in the ratio 3 : 1. Find each share.

   Formula:Dividing in a Ratio

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

   View formula →
10. 10.

    A triangle has a base of 34 cm and a height of 28 cm. Find its area.

    Formula:Area of a Triangle

    $A = \tfrac{1}{2} b h$

    View formula →
11. 11.

    A cylinder has radius 12 cm and height 18 cm. Find its volume. (π ≈ 3.14159)

    Formula:Volume of a Cylinder

    $V = \pi r^2 h$

    View formula →
12. 12.

    A triangle has a base of 20 cm and a height of 22 cm. Find its area.

    Formula:Area of a Triangle

    $A = \tfrac{1}{2} b h$

    View formula →
13. 13.

    A bag has 25 equally likely marbles, of which 24 are red. Find the probability of drawing a red marble (to 3 d.p.).

    Formula:Simple Probability

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

    View formula →
14. 14.

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

    Formula:Area of a Circle

    $A = \pi r^2$

    View formula →
15. 15.

    A triangle has a base of 20 cm and a height of 27 cm. Find its area.

    Formula:Area of a Triangle

    $A = \tfrac{1}{2} b h$

    View formula →
16. 16.

    An object has mass 333.2 g and volume 49 cm³. Find its density.

    Formula:Density

    $\rho = \dfrac{m}{V}$

    View formula →
17. 17.

    A car travels 300 km in 5 hours. Find its average speed.

    Formula:Speed

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

    View formula →
18. 18.

    A right-angled triangle has legs of 15 cm and 15 cm. Find the length of the hypotenuse.

    Formula:Pythagorean Theorem

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

    View formula →
19. 19.

    What is 25% of 340?

    Formula:Percentage of a Quantity

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

    View formula →
20. 20.

    A circle has a radius of 9 cm. Find its area. (Use π ≈ 3.14159)

    Formula:Area of a Circle

    $A = \pi r^2$

    View formula →

© FormulaWon — formulawon.app · Answers & step-by-step working available on the solutions sheet.