You may also like

problem icon

Ball Bearings

If a is the radius of the axle, b the radius of each ball-bearing, and c the radius of the hub, why does the number of ball bearings n determine the ratio c/a? Find a formula for c/a in terms of n.

problem icon

Far Horizon

An observer is on top of a lighthouse. How far from the foot of the lighthouse is the horizon that the observer can see?

problem icon

Air Routes

Find the distance of the shortest air route at an altitude of 6000 metres between London and Cape Town given the latitudes and longitudes. A simple application of scalar products of vectors.

Submit A Solution

We love to see solutions you send in to our live problems. We review and edit these for the benefit of other students. Check the Past Features links for published solutions to recently featured problems. The best solutions are likely to be featured in the Trending column.

If you would like us to consider including your solution please submit it while the problem is Live.

We have written an article on what we are looking for when we decide which solutions to publish.

Send your best solutions for Alternative Record Book;
Explain your methods clearly for other school students to read.
Give reasons and convincing arguments or proofs where you can.

You can now upload a file with your solutions eg. a picture,word document or spreadsheet,
this file must be less than 2MB
Your name, age and school are optional

Country: