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A boy is twice as old as his...

A boy is twice as old as his sister, and half as old as their father. In 50 years, his sister will be half as old as their father. How old is the boy now?

Correct answers: 66

The first user who solved this task is Sanja Šabović.

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Who said English is easy?

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Screw pointing and threading machine patent

In 1852, Cullen Whipple, of Providence, R.I., patented his "Mechanism for Pointing and Threading Screw-Blanks in the Same Machine" (U.S. No. 9477). His new design incorporated additional cutters in the same threading machine he had patented on 18 Aug 1842 (No. 2754, reissued 5 Mar 1850). Before machines provided a point on screws, they had blunt ends, and it was necessary to drill a starter hole. In Oct 1840, he was one of ten incorporators of The New England Screw Co. After his original thread-cutting machine, he invented another for shaving the heads of screws (patented 6 Apr 1843) and one for removing the burs left in cutting the slots in the heads (patented 19 Apr 1843). He patented seven other screw-manufacturing devices.«

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