Replace the question mark with a number
MATH PUZZLE: Can you replace the question mark with a number?Correct answers: 132
The first user who solved this task is H Tav.
#brainteasers #math #riddles
PhotophoneIn 1882, the photophone was demonstrated by Alexander Graham Bell and Charles Sumner Tainter. In their device, a mirrored silver disc was made to vibrate by speech from a speaking tube. Light reflected off the disc was focused by a parabolic dish onto a selenium photocell. The variations in the reflected light were converted into electrical signals carried to headphones. |