The 1961 GCE O-level exam included this question:
If one square yard of material costs 18 pence, what is the price of one square foot?
One student considered:
1 square yard costs 18 pence.
Therefore 1 yard costs 
Therefore 1 foot costs 4.243 ÷ 3 = 1.414 pence.
Therefore 1 square foot costs 1.4142 = 2 pence.
(Via Eureka.)