Which number should replace the question mark?Which number should replace the question mark?
Correct answers: 51
The first user who solved this task is Sanja Šabović.
#brainteasers #math #riddles
Electric mineIn 1841, an underwater torpedo operated by electric current was described by its inventor, Samuel Colt of Hartford, Conn., in a letter to U.S. President John Tyler. The invention was a combination of Robert Fulton's stationary torpedo and Prof. Robert Hare's galvanic current. Colt proved his mines could sink ships with a demonstration on 4 Jul 1842 sinking the gunboat Boxer in New York Harbor, and another on the following 18 Oct which sank the 300-ton brig Volta. By 13 Apr 1843, He was called upon to demonstrate to the President and his Cabinet, and Colt blew up a schooner on the Potomac River by an electric main from a distance of five miles.