Based on the information present in the given passage, you need to write a correct answer to the given question. A correct answer is one that correctly and completely answers the question. Do not write answers that address the question partially or incorrectly. The correct answer must be contained in the given paragraph.

[Q]: Paragraph- Sent 1: Soon after the conclusion of peace, important changes were made in legislation concerning industry and commerce, and the new freedom thus afforded produced a large number of limited liability companies.
Sent 2: Plans were formed for building a great network of railways, partly for the purpose of developing the natural resources of the country, and partly for the purpose of increasing its power for defense and attack.
Sent 3: The existence of serfdom was tackled boldly, taking advantage of a petition presented by the Polish landed proprietors of the Lithuanian provinces and, hoping that their relations with the serfs might be regulated in a more satisfactory way (meaning in a way more satisfactory for the proprietors), he authorized the formation of committees "for ameliorating the condition of the peasants," and laid down the principles on which the amelioration was to be effected.
Sent 4: This step had been followed by one even more significant.
Sent 5: Without consulting his ordinary advisers, Alexander ordered the Minister of the Interior to send a circular to the provincial governors of European Russia (serfdom was rare in other parts), containing a copy of the instructions forwarded to the Governor-General of Lithuania, praising the supposed generous, patriotic intentions of the Lithuanian landed proprietors, and suggesting that perhaps the landed proprietors of other provinces might express a similar desire.
Sent 6: The hint was taken: in all provinces where serfdom existed, emancipation committees were formed.
Sent 7: The emancipation was not merely a humanitarian question capable of being solved instantaneously by imperial ukase.
Sent 8: It contained very complicated problems, deeply affecting the economic, social and political future of the nation.
Sent 9: Alexander had to choose between the different measures recommended to him and decide if the serfs would become agricultural laborers dependent economically and administratively on the landlords or if the serfs would be transformed into a class of independent communal proprietors.
Sent 10: The emperor gave his support to the latter project, and the Russian peasantry became one of the last groups of peasants in Europe to shake off serfdom.
Sent 11: The architects of the emancipation manifesto were Alexander's brother Konstantin, Yakov Rostovtsev, and Nikolay Milyutin.
Sent 12: On 3 March 1861, 6 years after his accession, the emancipation law was signed and published.
Question: When was the existence of serfdom tackled?.
[A]: Soon after the conclusion of peace.

[Q]: Paragraph- Sent 1: Speed is an important aspect of motion.
Sent 2: It is a measure of how fast or slow something moves.
Sent 3: To determine speed you must know two things.
Sent 4: First, you must know how far something travels.
Sent 5: Second, you need to know how long it takes to travel that far.
Sent 6: Speed can be calculated using this formula: speed = distance time A familiar example is the speed of a car.
Sent 7: In the U.S., this is usually expressed in miles per hour.
Sent 8: Think about a trip you and your family made in the car.
Sent 9: Maybe the trip covered 120 miles and it took 3 hours.
Sent 10: What was the cars speed?
Sent 11: speed = 120 mi = 40 mi/h 3h The speed of a car may also be expressed in kilometers per hour (km/h).
Sent 12: The SI unit for speed is meters per second (m/s).
Sent 13: This is the unit of measure a scientist would use.
Question: What is speed?.
[A]: Speed is an important aspect of motion.

[Q]: Paragraph- Sent 1: Einstein and Maric married in January 1903.
Sent 2: In May 1904, the couple's first son, Hans Albert Einstein, was born in Bern, Switzerland.
Sent 3: Their second son, Eduard, was born in Zurich in July 1910.
Sent 4: In 1914, the couple separated; Einstein moved to Berlin and his wife remained in Zurich with their sons.
Sent 5: They divorced on 14 February 1919, having lived apart for five years.
Sent 6: Eduard, whom his father called "Tete" (for petit), had a breakdown at about age 20 and was diagnosed with schizophrenia.
Sent 7: His mother cared for him and he was also committed to asylums for several periods, including full-time after her death.
Sent 8: The marriage with Maric does not seem to have been very happy.
Sent 9: In letters revealed in 2015, Einstein wrote to his early love, Marie Winteler, about his marriage and his still strong feelings for Marie.
Sent 10: In 1910 he wrote to her that "I think of you in heartfelt love every spare minute and am so unhappy as only a man can be" while his wife was pregnant with their second child.
Sent 11: Einstein spoke about a "misguided love" and a "missed life" regarding his love for Marie.
Sent 12: Einstein married Elsa Lowenthal on 2 June 1919, after having had a relationship with her since 1912.
Sent 13: She was a first cousin maternally and a second cousin paternally.
Sent 14: In 1933, they emigrated to the United States.
Sent 15: In 1935, Elsa Einstein was diagnosed with heart and kidney problems; she died in December 1936.
Question: Einstein and Elsa were married for?.
[A]:
17 years.