Maths quiz for Irish Rail

Sir, – I think I have a question that could be included in the Leaving Cert (higher level) maths exam this June.

According to the Transport for Ireland poster at Sean’s local train station, the Belfast train “operated as planned” and had a “100 per cent reliability” score for the time period September 19th to October 10th, 2022. During the same period, the Belfast train was also late by 10 minutes or less for “87.7 per cent” of the time.

(i) Explain how a train that was late by 10 minutes or less for 87.7 per cent of the time is 100 per cent reliable and operated as planned. Make sure you show your calculations.

(ii) Was the Belfast train on time, or was it late by more than 10 minutes, for 13.3 per cent of the time? Explain why your answer has no real solution. – Yours, etc,