Sarah wants to estimate the number of grasshoppers in a specific field.
She catches a sample of 60 grasshoppers. She marks each grasshopper with a small spot of non-toxic dye and releases them.
A week later, Sarah catches another sample of 40 grasshoppers from the same field. She finds that 8 of these grasshoppers have been marked with dye.
Work out an estimate for the total number of grasshoppers in the field.
Write down any assumptions you have made.
20 exam-style questions on Edexcel GCSE Maths Capture Recapture. Each one has a worked solution and a mark scheme showing where the marks go.