You may also like

problem icon

Rationals Between...

What fractions can you find between the square roots of 65 and 67?

problem icon

Canny Fraction

Weekly Problem 4 - 2012
What fraction of the volume of this can is filled with lemonade?

problem icon

Circuit Training

Mike and Monisha meet at the race track, which is 400m round. Just to make a point, Mike runs anticlockwise whilst Monisha runs clockwise. Where will they meet on their way around and will they ever meet at the start again? If so, after how many circuits?

Counting Fish

Age 14 to 16 Challenge Level:

Image (c)

I need a figure for the fish population in a lake.

I catch 40 fish and mark a scale on each fish so that they can be identified if caught again.

The fish are then released and one week later I once more catch 40 fish and look to see which of these I caught before.

How does this help me come up with a figure for the fish population in a lake?

What assumptions does this method of estimating the fish population rely on?
How do you think you could improve the accuracy of your estimate?

Click here for a poster of this problem.