Paper 22 Q19IGCSE 0580 May/June 2023

Question

19 m is inversely proportional to the square of (t+2). m=0.64 when t=3. Find m when t=8.

This question tests inverse proportion where one variable is inversely proportional to the square of an expression. Understanding this relationship allows you to find unknown values when the constant of proportionality is determined.

Step-by-Step Solution

Key Takeaway

In inverse proportion, multiply the given values to find the constant, then use this constant with the new variable value.

Common Mistakes

Writing m = k(t+2)^2 instead of m = k/(t+2)^2 - this would be direct proportion, not inverse
Forgetting to add 2 to t, using just t^2 in the denominator instead of (t+2)^2

Exam Tip

Always check your relationship makes sense: as t increases, (t+2)^2 increases, so m should decrease for inverse proportion.

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