Problem-Solving Approach

AO3 (problem solving) accounts for roughly 30% of the marks across your three Edexcel papers. These questions are where many students lose marks — not because the maths is too hard, but because they do not have a structured approach. This lesson gives you a framework.

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The "What Do I Know / What Do I Need" Framework

Before writing anything, ask yourself two questions:

1. What do I know? (List all the information given in the question.)
2. What do I need to find? (What is the question actually asking for?)

Then ask: What connects them? (Which mathematical technique bridges the gap?)

Example

Question: A cone has volume 150π cm³ and height 18 cm. Find the radius.

What do I know?

• Volume = 150π cm³
• Height = 18 cm
• Formula: V = ⅓πr²h (from formula sheet)

What do I need?

• The radius, r

What connects them?

• Substitute into the formula and solve for r.

150π = ⅓ × π × r² × 18 150π = 6πr² r² = 150π ÷ 6π = 25 r = 5 cm

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Breaking Multi-Step Problems into Parts