Question

Eggs were $2.05 per dozen on January 1st and $2.00 per dozen February 1st what percent did the price decrease during January?

Answer 1

This is a 2.5% decrease in price.

Answer 2

For this case we can make the following rule of three:
 2.05 $ -----> 100%
 2.00 $ -----> x
 Clearing x we have:
 x = (2.00 / 2.05) * (100)
 x = 97.5
 Then, the percentage that decreases is:
 100-97.5 = 2.5%
 Answer:
 the price did decrease 2.5% during January