Nimepitia maandiko mengi hii haikubaliki
Contrary to popular belief, there is only one correct spelling of the number 40.
Forty is the proper way to spell the number, and fourty is always incorrect. It’s easy to see why this would be confusing, since the base number is four, and the U isn’t dropped from other numbers like fourteen or even forty-four. While there are British and American spellings of some words, forty is not one of them.
The following sentences are correct:
Jon drove forty miles per hour in a thirty-five mile per hour zone.
Amanda ate forty hot dogs.
Melinda is forty-six years old.
The site has about forty full-time employees, mostly in New York, where the publication is based, and so far they have worked with more than nine hundred athletes, Robertson told me. –The New Yorker
When to Use Fourty
You should never use fourty. It is an incorrect spelling of forty. Fourty is not correct in British or American English, and it appears to have never been the correct spelling.