M3: Ratio, Proportion, Mixing and Rates
Official Cambridge & Imperial ESAT specification requirements for Ratio, Proportion, Mixing and Rates on the Mathematics 1 paper. Understand the syllabus boundaries, spot distractor traps engineered by examiners, and master the 2-step Sub-90 shortcuts that compress solve time well below the 88.8-second cutoff.
Official Syllabus Subtopics
Requirements specified in the UAT-UK framework
- 1Non-linear direct and inverse proportionality: y ∝ xⁿ and y ∝ 1/xⁿ
- 2Two-component mixing and dilution alligation
- 3Reverse percentage compounding and multi-period multiplier equations
- 4Combined work rates: 1/Tₜₒₜ = 1/t₁ + 1/t₂
- 5Geometric similarity scaling: linear factor k, area factor k², volume factor k³
- 6Cone frustums and proportional volume slicing
Sub-90 Exam Speed Tips
How top candidates solve this spec under the 88.8s clock
For combined work rates, invert individual times to find work completed per hour and sum the rates directly.
When scaling geometric solids, verify whether the question asks for linear, surface area, or volume ratios.
Examiners engineer distractor options using common algebraic expansions and sign slips. Always test structural ratios or invariants before calculating arithmetic values.
Tested Topics in Specification M3
Master the individual question patterns and Sub-90 shortcuts for this specification.
Non-Linear Proportionality (y ∝ xⁿ) & Reverse Percentage Compounding
Never solve for proportionality constant k: write y2/y1 = (x2/x1)ⁿ directly using fractional multipliers (e.g. +20% = 6/5, -25% = 3/4). For reverse percentages, divide by the multiplier.
Two-Component Mixing, Dilution Alligation & Combined Work Rates
Lock onto the invariant quantity (pure solute or pure metal) that does not change during dilution: C1*V1 = C2*V2. For two mixtures C1 and C2 making Cₘ, the volume ratio is |C2 - Cₘ| : |Cₘ - C1|.
2D/3D Geometric Similarity Scaling (k, k², k³) & Frustums
Write the scaling triad L : A : V = k : k² : k³ immediately. For a frustum cut at fraction k of height from apex, V(frustum) = (1 - k³) * V(whole).
Ready to Master Specification M3 Under Exam Conditions?
Practice timed questions under the authentic Pearson VUE interface with live split stopwatch pacing, dry-wipe scratchpad, and distractor forensics.