Sian wants to estimate the number of birds in a woodland area. She catches 60 birds, attaches a ring to their leg and releases them. Later, she catches a sample of 45 birds and finds that 15 of them have rings.
Calculate an estimate for the total number of birds in the woodland.
Write down any assumptions you have made.
87 exam-style questions on Eduqas GCSE Maths Capture Recapture. Each one has a worked solution and a mark scheme showing where the marks go.