Bhavna has a bag containing a large number of beads.
She wants to find an estimate for the number of beads in the bag.
Bhavna takes a sample of 40 beads from the bag.
She marks each bead with a black cross.
She then puts the beads back in the bag.
Bhavna shakes the bag.
She now takes another sample of 40 beads from the bag.
16 of these beads have been marked with a black cross.
Work out an estimate for the total number of beads in the bag.
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.