1. Word problem solving is shoddy at best. There is a lot of functionality of Wolfram Alpha that exists for that minuscule chance that somebody will actually query it, so queries matching "[person has object]*, what is the total" is easily understood but it fails when the database doesn't have "mango" or the plural "mangoes" tagged as an object. This is largely due to poor database design decisions made in the past, but I know that this will improve in the future based on the project I worked on in improving the standard data format.
2. Some functionality is literally only for the sake of demonstration. I remember one time when Stephen was demonstrating a variety of cool queries into Wolfram Alpha during the yearly all-staff meeting, and when I got back to my desk I tried all the same queries with slight variations and almost all of them failed.
3. Mathematica has powerful string manipulation and regex matching functionality, to the point where lazy engineers are easily tempted to join the dark side. So it is very possible that this particular word problem only works because of a regex match. I know it sounds crazy, but I honestly wouldn't be surprised if some lazy engineer added in a literal match for "([subject] (have|has) [number] (apple|apples|orange|pear|peach|peaches))+", fed it into a simple extraction function, and output the result.
Comments
There are three things to note here:
1. Word problem solving is shoddy at best. There is a lot of functionality of Wolfram Alpha that exists for that minuscule chance that somebody will actually query it, so queries matching "[person has object]*, what is the total" is easily understood but it fails when the database doesn't have "mango" or the plural "mangoes" tagged as an object. This is largely due to poor database design decisions made in the past, but I know that this will improve in the future based on the project I worked on in improving the standard data format.
2. Some functionality is literally only for the sake of demonstration. I remember one time when Stephen was demonstrating a variety of cool queries into Wolfram Alpha during the yearly all-staff meeting, and when I got back to my desk I tried all the same queries with slight variations and almost all of them failed.
3. Mathematica has powerful string manipulation and regex matching functionality, to the point where lazy engineers are easily tempted to join the dark side. So it is very possible that this particular word problem only works because of a regex match. I know it sounds crazy, but I honestly wouldn't be surprised if some lazy engineer added in a literal match for "([subject] (have|has) [number] (apple|apples|orange|pear|peach|peaches))+", fed it into a simple extraction function, and output the result.