Thirty seven wells in Tallahassee were tested in July, 1989. Thirteen of these wells were contaminated. What percent of the wells were contaminated?

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Answer 1 · 2016-12-21T14:58:35

35.1% of the wells were contaminated.

"Percent" or "%" means "out of 100" or "per 100" or #w/100#.

We can then write this problem as:

#13:37 = w/100#

or

#13/37 = w/100#

Now we solve for #w#:

#color(red)(100) xx 13/37 = color(red)(100) xx w/100#

#1300/37 = color(red)(cancel(color(black)(100))) xx w/color(red)(cancel(color(black)(100)))#

#1300/37 = w#

#35.1 = w# rounded to the nearest 10th.