instruction:
This task involves creating questions from a given passage that involve some kind of complex reasoning (including numerical reasoning). 
The generated questions must require looking at more than one part of the passage to answer. Try to use a variety of reasoning types in your questions (some of the sample reasoning types are illustrated in the 'positive examples' field) and also have a variety of answer types (spans, numbers, dates). A span is a continuous phrase taken directly from the passage or question. In such questions, the answer spans are recommended to be five words. Questions with answer type "number", are expected to start with "How many". For instance, "How long did an event last?" can be phrased as "How many years did an event last?". To increase diversity, try to create more questions for which the answer will be multiple spans. Please create questions that require AT LEAST 2 arithmetic operations as illustrated in the 'positive examples' field. You are encouraged to try DIFFERENT COMBINATIONS of operations and not just limit to the combinations shown in those examples. The more challenging questions you create, the better it is.
question:
Passage: The United States Navy (USN) hoped to use the V-1710 in its rigid airships USS Akron (ZRS-4) and USS Macon (ZRS-5), but both were equipped with German-built Maybach VL-2 engines as the V-1710 was still in testing when the Macon was lost in February 1935 (the Akron having been lost in April 1933). The USAAC purchased its first V-1710 in December 1932. The Great Depression slowed development, and it was not until December 14, 1936 that the engine next flew in the Consolidated XA-11A testbed. The V-1710-C6 successfully completed the USAAC 150 hour Type certificate on April 23, 1937 at , the first engine of any type to do so. The engine was then offered to aircraft manufacturers where it powered the prototype Curtiss XP-37s. All entrants in the new pursuit competition were designed around it, powering the Lockheed P-38, Bell P-39 and Curtiss P-40. When war British Purchasing Commission asked North American Aviation to build the P-40 under license, NAA instead proposed their own improved aircraft design, using the V-1710 in their North American P-51 Mustang.
answer:
How many airships did the United States Navy (USN) hope to use the V-1710 in?


question:
Passage: As of the census of 2000, there were 18,812 people, 7,402 households, and 5,477 families residing in the county.  The population density was 55 people per square mile (21/km²).  There were 10,319 housing units at an average density of 30 per square mile (12/km²).  The racial makeup of the county was 51.45% Race (United States Census), 41.90% Race (United States Census) or Race (United States Census), 0.20% Race (United States Census), 0.66% Race (United States Census), 0.04% Race (United States Census), 0.82% from Race (United States Census), and 0.92% from two or more races.  2.16% of the population were Race (United States Census) or Race (United States Census) of any race.
answer:
How many households and families are in the county according to the census?


question:
Passage: The 2010 United States Census reported that Placer County had a population of 348,432. The racial makeup of Placer County was 290,977 (83.5%) White (U.S. Census), 4,751 (1.4%) African American (U.S. Census), 3,011 (0.9%) Native American (U.S. Census), 20,435 (5.9%) Asian (U.S. Census), 778 (0.2%) Pacific Islander (U.S. Census), 13,375 (3.8%) from Race (United States Census), and 15,105 (4.3%) from two or more races.  Hispanic (U.S. Census) or Latino (U.S. Census) of any race were 44,710 persons (12.8%).
answer:

How many in percent from the census weren't African American?