I don't work for Apple, and of course they don't share their marketing strategies with me, but we can more or less accurately reverse engineer their target demographic by looking at the product itself.
The iPad sells for between $500 and $800, depending on which one you buy and where. It is also a novelty item that, while highly functional, is not absolutely necessary in business or education. This makes it appealing to a different target group for marketing purposes.
Purchasers of the iPad, in my opinion, tend to include college students, business travelers, tech savvy consumers and the wealthy. It will tend to be marketed more towards whites, more towards males, and those making more than $50,000 per year or who attend affluent colleges. The target demographic in terms of age would be, to me, those between the ages of 18 - 50, with a geographic target of urban environments.