math/fractions
posted by yolanda .
Beth bought a shirt for $6. This was 1/5 of the regular price. What was the regular price of the shirt?

You may need to set up a ratio and crossmultiply:
6/x : 1/5
If you crossmultiply  6•5 and 1•x  what's the result? That will be the "regular price" of the shirt.
http://www.aaastudy.com/rat.htm#topic7