Sonia works in quality control at a factory that makes car radios. One week she found 18 defective radios. This represents 0.8% of the number of radios produced. How many radios did the factory produce that week?

0.8% as a fraction = 8/1000

You may be wondering why 0.8% isn't equal to 8/100. That is because only 8% is equal to 8/100.

0.8% is smaller than 1%!

So, 8/1000 of the variable x is equal to 18, where x is the total number of radios.

8x/100 = 18

8x = 1800

x = 225

225 radios produced.

The factory produced 225 radios that week!