A scientist wants to estimate the population of ants in a colony.
She catches 100 ants and marks each one with a tiny dot of paint. She then returns the ants to the colony.
Later that day, she catches another sample of 120 ants. 15 of these ants have a dot of paint on them.
Work out an estimate for the total number of ants in the colony.
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.