Can any explain

if the following is correct,

A percentage decrease of 10% is equal to a price ratio of 0.1

is a price ratio of 0.4 equal to a a price decrease of 40 % ???

Any advice appreciated !!

thanks

It depend on what you take as the "price ratio"

Normally, if something decreases by ten percent, its new price is considered to be ninety percent, or the ratio of the new price to the old price is .9

and a decrease of forty percent would lead to a price ratio of .6