Calculate the number 561
NUMBERMANIA: Calculate the number 561 using numbers [2, 3, 2, 9, 76, 660] and basic arithmetic operations (+, -, *, /). Each of the numbers can be used only once.Correct answers: 1
#brainteasers #math #numbermania
Thomas DavenportDied 6 Jul 1851 at age 48 (born 9 Jul 1802). American inventor of what was probably the first commercially successful electric motor, which he used with great ingenuity to power a number of established inventions. Though several other inventors had experimented with motors, Davenport was the first to secure a US patent (No. 132 on 25 Feb 1837) for his direct current motor. He incorporated the concept of the electromagnet invented by Joseph Henry in a way that produced a rotary motion using his own idea of a commutator and brushes to control the direction of current flow. He used a motor he built to power shop machinery, and also built the first electric model railroad car. |