In this task, you're given passages that contain mentions of a time duration related quesry and we are supposed to write answer to a question that involves event “frequency", which refers to how often an event is likely to be repeated. For example, "taking showers" typically occurs ~5 times a week, "going to saturday market" usually happens every few weeks/months, etc. 
 Note that a lot of the questions could have more than one correct answers. We only need a single most-likely answer. Please try to keep your "answer" as simple as possible. Concise and simple "answer" is preferred over those complex and verbose ones.  

Sentence: Uranium's average concentration in the Earth's crust is (depending on the reference) 2 to 4 parts per million, or about 40 times as abundant as silver. The Earth's crust from the surface to 25 km (15 mi) down is calculated to contain 1017 kg (2×1017 lb) of uranium while the oceans may contain 1013 kg (2×1013 lb). The concentration of uranium in soil ranges from 0.7 to 11 parts per million (up to 15 parts per million in farmland soil due to use of phosphate fertilizers), and its concentration in sea water is 3 parts per billion. 
Question: How many times more abundant than silver is uranium in the Earth's crust?
40

Sentence: iPods have been criticized for alleged short life-span and fragile hard drives. A 2005 survey conducted on the MacInTouch website found that the iPod line had an average failure rate of 13.7% (although they note that comments from respondents indicate that "the true iPod failure rate may be lower than it appears"). It concluded that some models were more durable than others. In particular, failure rates for iPods employing hard drives was usually above 20% while those with flash memory had a failure rate below 10%. In late 2005, many users complained that the surface of the first generation iPod Nano can become scratched easily, rendering the screen unusable. A class action lawsuit was also filed. Apple initially considered the issue a minor defect, but later began shipping these iPods with protective sleeves.[citation needed] 
Question: What website ran a survey to learn how often iPods ceased working?
MacInTouch

Sentence: The two became friends, and for many years lived in close proximity in Paris, Chopin at 38 Rue de la Chaussée-d'Antin, and Liszt at the Hôtel de France on the Rue Lafitte, a few blocks away. They performed together on seven occasions between 1833 and 1841. The first, on 2 April 1833, was at a benefit concert organized by Hector Berlioz for his bankrupt Shakespearean actress wife Harriet Smithson, during which they played George Onslow's Sonata in F minor for piano duet. Later joint appearances included a benefit concert for the Benevolent Association of Polish Ladies in Paris. Their last appearance together in public was for a charity concert conducted for the Beethoven Memorial in Bonn, held at the Salle Pleyel and the Paris Conservatory on 25 and 26 April 1841. 
Question: How many times did Chopin and Liszy perform together in public?

seven