In his first 25 trips to a swimming baths 

a man swims an average of five lengths each time. 

When he has totalled 100 visits to the baths 

the average number of lengths has risen to eight each time. 

What is the average number of lengths he swam per visit in the last 75 visits only? 

For a chance to win one of three ambigram mugs, simply e-mail the correct answer together with your full name and address to the Puzzle Editor

Train Your Brain?

Closing date is 30 September 2008.

The first three correct entries selected will be declared the winners and will be notified by the competition judges. The judge's decision is final; no correspondence will be entered into. Congratulations to last month's winners: S Samuel, Bucks, V Falconer, Vale of Glamorgan, Z Homes, Lincs. The correct answer was: 27