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Lintel Mar 9 - 15 25 questions
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Monday 9 March 2026

Keystones #68 · Five questions · Open this day only

  1. 1. Number

    Write 60 as a product of its prime factors

    Answer: 2² × 3 × 5
  2. 2. Algebra

    Solve: 2x + 3y = 35 and 3x - y = 14

    Answer: x = 7, y = 7
  3. 3. Geometry

    Calculate the missing side: a = 10cm, c = 24cm

    Answer: 21.8cm
  4. 4. Ratio

    a:b is 3:2 and b:c is 1:3. Find a:b:c.

    Answer: 3:2:6
  5. 5. Statistics

    A bag has 2 red out of 13 balls. If you pick 80 times (with replacement), how many times would you expect red?

    Answer: 12.3

Tuesday 10 March 2026

Keystones #69 · Five questions · Open this day only

  1. 1. Number

    Write 90 as a product of its prime factors

    Answer: 2 × 3² × 5
  2. 2. Algebra

    Solve: 2x + 3y = 32 and 3x - y = 15

    Answer: x = 7, y = 6
  3. 3. Geometry

    Find b if a = 14cm and c = 25cm

    Answer: 20.71cm
  4. 4. Ratio

    a:b is 2:3 and b:c is 4:5. Find a:b:c.

    Answer: 8:12:15
  5. 5. Statistics

    A bag has 5 red out of 15 balls. If you pick 95 times (with replacement), how many times would you expect red?

    Answer: 31.7

Wednesday 11 March 2026

Keystones #70 · Five questions · Open this day only

  1. 1. Number

    Express 144 as a product of prime factors

    Answer: 2⁴ × 3²
  2. 2. Algebra

    Solve: 2x + 3y = 10 and 2x + y = 6

    Answer: x = 2, y = 2
  3. 3. Geometry

    Calculate the missing side: a = 15cm, c = 32cm

    Answer: 28.3cm
  4. 4. Ratio

    a:b is 3:4 and b:c is 1:3. Find a:b:c.

    Answer: 3:4:12
  5. 5. Statistics

    A fair coin is flipped 110 times. How many heads would you expect?

    Answer: 55

Thursday 12 March 2026

Keystones #71 · Five questions · Open this day only

  1. 1. Number

    Express 120 as a product of prime factors

    Answer: 2³ × 3 × 5
  2. 2. Algebra

    Solve: 4x + 3y = 41 and x + y = 11

    Answer: x = 8, y = 3
  3. 3. Geometry

    Find b if a = 9cm and c = 15cm

    Answer: 12cm
  4. 4. Ratio

    a:b is 2:1 and b:c is 3:4. Find a:b:c.

    Answer: 12:6:8
  5. 5. Statistics

    A fair coin is flipped 154 times. How many heads would you expect?

    Answer: 77

Friday 13 March 2026

Keystones #72 · Five questions · Open this day only

  1. 1. Number

    Express 100 as a product of prime factors

    Answer: 2² × 5²
  2. 2. Algebra

    Solve: 2x + 3y = 24 and 3x - y = 25

    Answer: x = 9, y = 2
  3. 3. Geometry

    Calculate the missing side: a = 12cm, c = 28cm

    Answer: 25.3cm
  4. 4. Ratio

    a:b is 3:4 and b:c is 1:2. Find a:b:c.

    Answer: 9:12:24
  5. 5. Statistics

    A bag has 4 red out of 15 balls. If you pick 54 times (with replacement), how many times would you expect red?

    Answer: 14.4