Question

Fifty-four of the 90 books on a shelf are history books. What percent of the books are history books?

Answer 1

Divide 54 by 90 and then multiply the resulting decimal by 100 to convert to a percent.
54 / 90 = 0.60, then 0.60 * 100 = 60%

Answer 2

Thankies. :)

Answer 3

You could also set up a proportion:

54/90 = x/100
and solve for x via cross products.