Detailed Instructions: 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.
Problem:Passage: For domestic use, powered by 13,500 lb (60.5 kN) Pratt & Whitney JT3C-6 turbojets with water injection. The initial DC-8-11 model had the original, high-drag wingtips and all were converted to DC-8-12 standard. The DC-8-12 had the new wingtips and leading edge slot, 80 inches long between the engines on each wing and 34 inches long inboard of the inner engines. These unique devices were covered by doors on the upper and lower wing surfaces that opened for low speed flight and closed for cruise. The maximum weight increased from . 28 DC-8-10s were built. This model was originally named "DC-8A" until the series 30 was introduced. 29 built, 22 for United and 6 for Delta, plus the prototype. By the mid sixties United had converted 15 of its 20 surviving aircraft to DC-8-20 standard and the other 5 to -50s. Delta converted its 6 to DC-8-50s.
Solution:
How many more DC-8-10 were built for United than Delta?