Ireland · Year 8 · Practice Sheet 14

1. 1.

   What is 20% of 440?

   Formula:Percentage of a Quantity

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

   View formula →
2. 2.

   A bag has 30 equally likely marbles, of which 23 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 car travels 140 km in 4 hours. Find its average speed.

   Formula:Speed

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

   View formula →
4. 4.

   Solve for x: 6x + 18 = 42.

   Formula:Solving a Linear Equation

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

   View formula →
5. 5.

   A bag has 8 equally likely marbles, of which 3 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 →
6. 6.

   A right-angled triangle has legs of 18 cm and 12 cm. Find the length of the hypotenuse.

   Formula:Pythagorean Theorem

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

   View formula →
7. 7.

   An object has mass 360.8 g and volume 41 cm³. Find its density.

   Formula:Density

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

   View formula →
8. 8.

   Find the circumference of a circle whose radius is 20 m. (Use π ≈ 3.14159)

   Formula:Circumference of a Circle

   $C = 2\pi r$

   View formula →
9. 9.

   A circle has a radius of 7 cm. Find its area. (Use π ≈ 3.14159)

   Formula:Area of a Circle

   $A = \pi r^2$

   View formula →
10. 10.

    Find the circumference of a circle whose radius is 22 m. (Use π ≈ 3.14159)

    Formula:Circumference of a Circle

    $C = 2\pi r$

    View formula →
11. 11.

    Find the mean (average) of these numbers: 16, 21, 61, 86, 58, 76.

    Formula:Arithmetic Mean

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

    View formula →
12. 12.

    A circle has a radius of 24 cm. Find its area. (Use π ≈ 3.14159)

    Formula:Area of a Circle

    $A = \pi r^2$

    View formula →
13. 13.

    Find the mean (average) of these numbers: 92, 39, 66, 45, 87.

    Formula:Arithmetic Mean

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

    View formula →
14. 14.

    A value changes from 119 to 101. Find the percentage change (to 2 d.p.).

    Formula:Percentage Change

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

    View formula →
15. 15.

    €2,700 is invested at 10% simple interest per year for 3 years. Find the interest earned.

    Formula:Simple Interest

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

    View formula →
16. 16.

    What is 50% of 530?

    Formula:Percentage of a Quantity

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

    View formula →
17. 17.

    A car travels 200 km in 4 hours. Find its average speed.

    Formula:Speed

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

    View formula →
18. 18.

    Find the mean (average) of these numbers: 87, 83, 83, 39, 88, 75.

    Formula:Arithmetic Mean

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

    View formula →
19. 19.

    €200 is shared in the ratio 2 : 3. Find each share.

    Formula:Dividing in a Ratio

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

    View formula →
20. 20.

    A current of 3.4 A flows through a 12 Ω resistor. Find the voltage across it.

    Formula:Ohm's Law

    $V = I R$

    View formula →

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