What number should replace the question mark? 

35 ............... 8 

20 ............... 5 

70 ............... 15 

105 ............. 22 

10 ............... ?  

For a chance to win one of two Mensa Brain Trainer hand held consoles, simply e-mail the correct answer together with your full name and address to the Puzzle Editor

Train Your Brain?

Closing date is 31 July 2009.

The first two 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: B Marshall, London and T Lunn, Cheltenham. The answer was 39.