When all is not as it seems

The company HR director and CEO had carefully interviewed a dozen people for the job of assistant to the financial director. 

The chief executive thought that one candidate - Charles - seemed ideal. 

Charles had been to a major public school. Not only was he a qualified accountant, but Charles also had a masters degree in business administration. 

He seemed fully aware of the latest creative accountancy techniques. 'Charles,' said the chief executive, we've decided to offer you the job. 

And as you're so well qualified we've decided to start you off on a slightly higher salary than the one advertised. We'll pay you £120,000 a year. 

 'Thank you,' replied Charles. 'But how much is that per month?