ERJ Brainteaser - April
30 Mar 2026
Each month, ERJ sets a weekly brainteaser, with questions of varying degrees of difficulty. Readers supplying the most accurate (and stylish) answers are then considered for the prestigious Brainiac of the Month title
Moulded rubber seals are produced in pairs - one green, the other black - and transferred to containers holding more than 250 but less than 350 of the mouldings in total.
However, one seal has been lost from a container so that, if two seals were randomly drawn out, the probability of them being the same colour would be exactly 50%.
If there are more green seals than black seals, can you work out mathematically the colour of the missing seal?
Email your answer: correct replies on Friday.
