Ravina wants to find the number of tagged birds in a sample of birds in a sanctuary.
She catches a sample of 70 birds in the sanctuary and tags each of these birds.
These birds are then released back into the sanctuary.
The next day she catches a sample of 60 birds in the sanctuary.
Ravina knows that the estimate for the number of birds in the sanctuary is 350.
Work out the number of tagged birds in the second sample.
Write down an assumption 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.