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

Question

1782 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-12-21T14:58:35

35.1% of the wells were contaminated.

"Percent" or "%" means "out of 100" or "per 100" or $\frac{w}{100}$ $w/100$ .

We can then write this problem as:

$13 : 37 = \frac{w}{100}$ $13:37 = w/100$

or

$\frac{13}{37} = \frac{w}{100}$ $13/37 = w/100$

Now we solve for $w$ $w$ :

$100 \times \frac{13}{37} = 100 \times \frac{w}{100}$ $color(red)(100) xx 13/37 = color(red)(100) xx w/100$

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

$1300/37 = w$

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