Beth wants to estimate the number of frogs in a lake.
She catches a sample of 72 frogs, marks them and puts them back in the lake.
Later that day, in a second sample of 72 frogs, she finds that 9 of them are marked.
Work out an estimate for the number of frogs in the lake.
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.