MATH PUZZLE: Can you replace...MATH PUZZLE: Can you replace the question mark with a number?
Correct answers: 929
The first user who solved this task is Дејан Шкребић.
#brainteasers #math #riddles
Brush's dynamoIn 1877, a U.S. patent was issued to Charles F. Brush for his first dynamo, which he had first assembled in the summer of 1876. The patent was titled Improvement in Magneto-Electric Machines, (US No. 189997). Brush was a U.S. inventor and industrialist who also devised an electric arc lamp and a generator that produced a variable voltage controlled by the load and a constant current. It was adopted throughout the United States and abroad during the 1880's. The arc light preceded Edison's incandescent light bulb in commercial use and was suited to applications where a bright light was needed, such as street lights and lighting in commercial and public buildings.