Teacher: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Teacher: Now, understand the problem? If you are still confused, see the following example:
Passage: The French and Indian War (1754–1763) was the North American theater of the worldwide Seven Years' War. The war was fought between the colonies of British America and New France, with both sides supported by military units from their parent countries of Great Britain and France, as well as Native American allies. At the start of the war, the French North American colonies had a population of roughly 60,000 European settlers, compared with 2 million in the British North American colonies. The outnumbered French particularly depended on the Indians. Long in conflict, the metropole nations declared war on each other in 1756, escalating the war from a regional affair into an intercontinental conflict.
Solution: When was the French and Indian War?
Reason: This question is based on the following sentence in the passage- The French and Indian War (1754–1763) was the North American theater of the worldwide Seven Years' War. It is a common convention to write (start year-end year) beside a historical event to understand when the event happened. You can ask questions like this one about dates, years, other numerals, persons, locations, noun phrases, verb phrases, adjectives, clauses etc. which exist in the paragraph.

Now, solve this instance: 50 Hz systems support three scanning rates: 50i, 25p and 50p. 60 Hz systems support a much wider set of frame rates: 59.94i, 60i, 23.976p, 24p, 29.97p, 30p, 59.94p and 60p. In the days of standard definition television, the fractional rates were often rounded up to whole numbers, e.g. 23.976p was often called 24p, or 59.94i was often called 60i. 60 Hz high definition television supports both fractional and slightly different integer rates, therefore strict usage of notation is required to avoid ambiguity. Nevertheless, 29.97i/59.94i is almost universally called 60i, likewise 23.976p is called 24p.
Student:
What three scanning rates do 50 Hz systems support?