Why were slaves from Africa preferred in North America over other types of forced labor (Native American slaves or European indentured servants)?

Some slaves from North America had "experience" (for lack of a better word) working in fields. Some had been enslaved before, and has an understanding of the work they may face.

Hope this helps!

-AxekickNebulite

part a. there were 250 teenagers surveyed (100% of tenagers = 250)therefore 1 % = 250/100 = 2.5 76% = 1% x 76 = 2.5 x 76 = 190 teenagers of the 250 surveyed liked burgerspart b: jane surveyed 25% (which is equal to 50 teenagers, i.e. a quarter of the teenagers surveyed is 50) to get 100% we simply get 4 quarters, i.e. multiply 50 by 4 = 200 teenagers were surveyed by jane. part c: it is impossible to give an example where a percentage is greater than 100%, since, by definition , percentage means "per 100".