Can you replace the question mark with a number?
MATH PUZZLE: Can you replace the question mark with a number?Correct answers: 91
The first user who solved this task is Fazil Hashim.
#brainteasers #math #riddles
Fountain pen patentIn 1894, George Parker was issued a U.S. patent for a fountain pen design that became the Parker Pen Company's first major success. The Lucky Curve was designed to solve the problem that previous pens, while carried in a pocket, retained ink in the feed tube. Warmed by body temperature, the ink expanded forcing ink from the pen point into the cap and onto the barrel, causing soiled fingers on next use. The Lucky Curve design used capillary attraction to completely drain ink from the feed tube. Parker held several earlier fountain pen patents since his first on 10 Dec 1889. In Feb 1892, with partner W.E Palmer, he incorporated the Parker Pen Company to market his pens, and he continued to focus on making design improvements. |