The QWERTY keyboard was designed to slow typists down.
Why it is true
In the 1870s, fast typing on mechanical typewriters caused keys to jam. The layout placed common letter pairs apart, forcing typists to slow down.
Source: Technology History
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.