Can you replace the question mark with a number?
MATH PUZZLE: Can you replace the question mark with a number?Correct answers: 60
The first user who solved this task is Nasrin 24 T.
#brainteasers #math #riddles
Charles Benjamin DudleyDied 21 Dec 1909 at age 67 (born 14 Jul 1842).American chemical engineer who was an early supporter of standardisation and material testing in industry. From 1875, as a chemist for the Pennsylvania Railroad Company, he researched the metallurgy of steel rail tracks because their breakage was a serious hazard at that time. When he discovered enormous variation in the quality of steel and published his results (1878), the manufacturers were at first uncooperative. However, Dudley insisted on continuing testing, and rigorous standards for fuels, lubricants, paints, lighting devices and various mechanical parts of locomotives and rolling stock. He co-founded (1898) the American Society for Testing and Materials, and was its president from 1902 until his death.« |