Skip to main content
O-LevelMathematicsNumber4024/11 · Oct/Nov 2020 · Q245 Marks

Express 99 as the product of prime factors.

  1. (a)Express 99 as the product of prime factors.[1]
  2. (b)(i)Expressed as the product of prime factors, p = 2ⁿ⁺²×3ⁿ×5 and q = 2ⁿ×3ⁿ⁺¹×5² where n is a positive integer. The lowest common multiple (LCM) of p and q is 2ⁿ⁺²×3ⁿ⁺¹× R. Express R as the product of prime factors.[2]
  3. (b)(ii)Express p+q as the product of prime factors.[2]

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2020). The mark or mark type is shown in brackets.

  1. [1] 3² × 11 or 3 × 3 × 11
  2. [2] 2² × 3 × 5²
  3. B1 for [p =] [2ⁿ × 3ⁿ] × 2² × 5
  4. or for [q =] [2ⁿ × 3ⁿ] × 3 × 5²
  5. or for answer 300
  6. or M1 for [LCM =] 2ⁿ⁺² × 3ⁿ⁺¹ × 5²
  7. [2] 2ⁿ × 3ⁿ × 5 × 19 oe
  8. B1 for 2ⁿ × 3ⁿ × ... as the only powers of 2 and 3 in a product

Write your answer and get it marked

On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.

Sign up free →

About this question

Topic
Number, O-Level Mathematics (syllabus 4024). Structured question, 5 marks.
Source
O-Level Mathematics, Oct/Nov 2020 Paper 1 Variant 1, question 24.

Questions and mark schemes are from past examination papers and remain the copyright of the exam board. How Oracle Prep builds its content

Related Mathematics questions

© 2026 Oracle Prep