Capt BK, when transferring the formula to the cell, make sure that no extra spaces creep into it. Because of the formatting of this forum the formula breaks across several lines, and in copying this may lead to errors. In your post a space has appeared in front of the number 30, this may have caused the error (although I cannot reproduce the error by placing a space there, odd!
) also make sure there is no double apostrophe in front of the formula when it is in the cell.
Which version of Excel are you using, is it an English language version??
The reason Llademos method gives that answer is that it converts to a number, you should format the cell with the result as such and then you'll see '40'. It is now showing you 40 days displayed in hours.