A book costs $1 plus half it...
A book costs $1 plus half its price. How much does it cost?Correct answers: 69
The first user who solved this task is Djordje Timotijevic.
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Edison phonographIn 1877, Thomas Edison demonstrated his hand-cranked phonograph that recorded sound onto tinfoil cylinders. Although 12 Aug 1877, is often given as the date of this invention, it may have been only at the stage of a sketch, since Edison did not file for the patent until 24 Dec 1877. The idea came to Edison while working on a telegraph transmitter, when he noted that when the the tape of the machine was played at high speed, it gave off a noise resembling spoken words. After experimenting with a needle attached to the diaphragm of a telephone receiver to prick paper tape to record a message, his idea evolved to using a stylus on a tinfoil cylinder.«* |