For IndividualsFor Educators
ExpertMinds LogoExpertMinds
ExpertMinds

Ace your certifications with Practice Exams and AI assistance.

  • Browse Exams
  • For Educators
  • Blog
  • Privacy Policy
  • Terms of Service
  • Cookie Policy
  • Support
  • AWS SAA Exam Prep
  • PMI PMP Exam Prep
  • CPA Exam Prep
  • GCP PCA Exam Prep

© 2026 TinyHive Labs. Company number 16262776.

    PracticeAQA GCSEAQA GCSE Maths Higher Tier Paper 3 CalculatorQuestion 13
    Medium2 marksStructured
    ProbabilityHigherProbabilityWithout Replacement

    AQA GCSE · Question 13 · Probability

    A bag contains one £5 note, one £10 note, one £20 note and one £50 note. Amaan picks two of the notes at random without replacement. Work out the probability that he has picked at least £30.

    How to approach this question

    1. Determine the total number of possible outcomes. Since two notes are picked without replacement from four, think about how many choices there are for the first pick and then the second. 2. Identify what "at least £30" means (the sum is £30 or more). 3. List all the possible pairs of notes that can be picked. 4. For each pair, calculate the sum. 5. Count how many of these pairs have a sum of £30 or more. This is the number of favourable outcomes. 6. Calculate the probability by dividing the number of favourable outcomes by the total number of outcomes.

    Full Answer

    This is a probability problem without replacement. First, let's find the total number of ways Amaan can pick two notes. There are 4 choices for the first note. After picking one, there are 3 choices left for the second note. Total number of ordered pairs (outcomes) = 4 × 3 = 12. Next, let's find the number of pairs where the sum is at least £30 (i.e., £30 or more). We can list them systematically: - (£5, £10) = £15 (No) - (£5, £20) = £25 (No) - (£5, £50) = £55 (Yes) - (£10, £5) = £15 (No) - (£10, £20) = £30 (Yes) - (£10, £50) = £60 (Yes) - (£20, £5) = £25 (No) - (£20, £10) = £30 (Yes) - (£20, £50) = £70 (Yes) - (£50, £5) = £55 (Yes) - (£50, £10) = £60 (Yes) - (£50, £20) = £70 (Yes) Counting the "Yes" outcomes, we have 8 favourable outcomes. The probability is the number of favourable outcomes divided by the total number of outcomes. P(sum ≥ £30) = 8 / 12 This fraction can be simplified by dividing the numerator and denominator by their greatest common divisor, which is 4. P(sum ≥ £30) = 2 / 3.

    Common mistakes

    ✗ Forgetting that the order matters when listing outcomes, e.g., considering (£10, £20) but not (£20, £10). This leads to an incorrect total number of outcomes. ✗ Calculating with replacement (total outcomes would be 4x4=16). ✗ Misinterpreting "at least £30" as "more than £30".
    Question 12All questionsQuestion 14.1

    Practice the full AQA GCSE Maths Higher Tier Paper 3 Calculator

    32 questions · hints · full answers · grading

    Sign up freeTake the exam

    More questions from this exam

    Q01Work out the reciprocal of 10/3. Give your answer as a decimal.EasyQ02.1The table shows information about the number of houses with solar panels in a town. Complete the ...EasyQ02.2Use the graph to estimate the number of houses with solar panels in 2023.EasyQ03.1A building in the shape of a cylinder has diameter 40 m and height 55 m. On the centimetre grid, ...MediumQ03.2On this centimetre grid, draw the front elevation of the building. Use a scale of 1 cm to 10 m.Medium
    View all 32 questions →